"Purgatory Mount" by Adam Roberts is a breathtaking tapestry of cosmic mystery and human introspection. With his signature blend of deep philosophical inquiry and imaginative storytelling, Roberts crafts a narrative that straddles both the vastness of space and the intricacies of the human soul. As readers ascend the enigmatic mount, they are challenged with profound questions and mesmerizing scenarios. Roberts seamlessly melds speculative wonder with poignant human moments, creating a novel that's both intellectually stimulating and emotionally resonant. A must-read for those who seek depth in their science fiction.

It's one of those case "it's me not the book".
Even if the plot is complex and fascinating, the world building excellent i found it a bit confusing and the story didn't keep my attention.
It's the first book I read by this author and i think that reading his previous work would have helped.
Not my cup of tea.
Many thanks to the publisher and Netgalley for this ARC, all opinions are mine

No tenía pensado leer este Purgatory Mount tan pronto, pero si Alexander Paez te recomienda algo, es mejor que te pongas rápido con ese libro.


Las obras que he leído hasta ahora de Adam Roberts han sido bastante satisfactorias y esta no es una excepción. Es cierto que tiene una estructura un tanto extraña porque las dos tramas que la forman se conectan de una forma muy laxa. La primera y la última parte, que son cortas en comparación con la parte central, tienen un alto componente especulativo, con la exploración de un artefacto en un planeta lejano por parte de unos «humanos» tan evolucionados que son capaces de controlar el tiempo. Mientras tanto, la parte del león en cuanto a longitud de la novela se la lleva la parte central, con una relato de futuro muy cercano terriblemente verosímil.

Si hay algo que destaca en la obra de Adam Roberts es la cantidad de ideas que lanza al lector, a veces con una retranca inglesa que hay que aceptar y disfrutar. En este libro, por ejemplo, es capaz de hablar de Alzheimer usado como arma de destrucción masiva y a la vez del tratamiento de la enfermedad con un simple teléfono móvil. Roberts es capaz de estar narrando los estallidos de bombas tremendamente destructivas mientras parafrasea hits musicales de los últimos años. Su extenso conocimiento de la cultura clásica le permite hacer similitudes entre los personajes y los mitos griegos, pero en las últimas páginas de la obra nos hace ver que hubiera preferido con mucho utilizar los nombres de los magos del Señor de los Anillos, si no fuera por unos problemillas de copyright.

Aunque me han gustado las dos partes de la novela, personalmente hubiera preferido que se hubiera dedicado más a la parte más futurista de la novela, que me llamaba mucho más la atención que el grueso de libro. No obstante, he de reconocer que a pesar del desequilibro entre ambas tramas la lectura es más que interesante, y que yo hubiera preferido más hincapié en la otra parte es solo una preferencia personal. Resulta aterrador por lo verosímil cómo Adam Roberts narra la desintegración de los Estados Unidos, en una narración que podríamos describir como «Doctorowzada», si me permitís la expresión, basándose en los medios de control de masas y con protagonistas jóvenes atrapados por el sistema, como en Little Brother , Homeland y otras obras de Cory Doctorow.

El mensaje de redención y expiación de los pecados que lanza Roberts es también digno de estudio. El hecho de que el cielo y el infierno sean atemporales mientras que el purgatorio requiera por definición el paso del tiempo da lugar a una especulación filosófica bastante interesante. Como has podido ver, hay muchas razones por las que recomendar Purgatory Mount, espero que alguna de ellas te haya convencido.

Interstellar space travel, the discovery of new planets, evidence of ancient alien civilisations and first encounters still remains one of the more fascinating sides of science fiction. The apocalyptic and environmental catastrophe perhaps not so much at the minute as we seem to be rapidly heading towards living in a J. G. Ballard novel - not that Ballard's genius and vision has diminished at all. It remains fascinating because it's still largely a journey into the unknown and there are many technical advances that have to be achieved or imagined to get us there, advances nonetheless that can also be used for other purposes back on Earth.

Purgatory Mount opens with a journey to the planet y, the third Earth sized planet in the V538 Aurigae system, a mere 40 light years away. The five-man crew of the Forward are there to explore a tower that is not a natural phenomenon, but a vast pillar that extends 142 kilometres above the surface of the planet. The crew think of it like a structure that resembles the mountain of Purgatory in Dante's The Divine Comedy. Up to now there has been no evidence of alien civilisations, so the team intend to study it, discover its purpose - is it a space elevator or a spiritual structure? - and just as importantly discover whether any new technology can be learned from it.

Technological advancement is of course what has enabled the crew to get there and study. The most important advance evidently being the means used to enable humans to travel such distances. They use a kind of temporal cryogenics that slows down the human body, allowing each light year to pass in a week, travelling in fast forward while to all intents and purposes they move about the ship in infinitesimally slow motion. It's this ability to manipulate time that will also permit them to spend almost as long as they like studying the planet's strange structure.

Like every advancement in technology, there is a downside that has to be considered, since although the body can be enhanced to endure thousands of years in this state, the impact on the mind is rather more dangerous, so its use has to be exercised carefully. That's one issue, but Roberts also has a few other intriguing elements to bring in relating to the living food supplies of pygs, cows and chickens that also make the journey, as well as of course the ships hal, its AI intelligence.

Meanwhile back on Earth, things don't look particularly great. The United States is effectively a large police state, with riots erupting in New Jersey and there are some neighborhoods that are too dangerous to go venture out at any time of the day or night. Some of the technology seen in space, principally in relation to memory enhancement, is also deployed on Earth, where drones and robot mechanics are also used but with more sinister implications. It doesn't stop 16 year old Ottoline Barragāo, known as Otty from taking her chances scavenging for copper wire for a clandestine off-grid encrypted network she is building with some friends; a project that is getting unwelcome attention from the authorities.

Purgatory Mount is curiously laid out with two distinct parts. You think you know where it's going from the space travel opening, when suddenly it abruptly moves to Earth with little obvious connection. In fact it then practically forgets about the structure in space for a good two thirds of the novel, and makes no further reference to it. What we discover about what is happening back on Earth is potentially interesting but the perspective we get from Otty and her friends is restricted by their age and circumstances, and you only get hints of the huge upheaval taking place in the world outside. There are some fascinating surreal descriptions of future war, violence; the twists on technology all pointing to worrying developments, but it all seems less interesting than the promise of the early part of the novel on a distant planet.

The clincher is going to be how and even whether Roberts can meaningfully connect the two distinct parts of the book. He does of course, raising interesting questions on the nature of gods, spirituality, religion and where it intersects with science, morality and society. As a novel it's a little frustrating that it keeps you waiting so long for a twist or punchline and the in-between isn't always compelling, but when we get back to Purgatory Mount, the revelations, the impact of them and their meaning certainly make this worthwhile.

Purgatory Mount by Adam Roberts

In the far future, a spaceship carrying a crew of five human entities, the type that can live for thousands of years and regard themselves with godlike eyes, arrives at a distant planet and discovers an enormous artificial mountain, a tower that soars into the sky. For everyone on the vessel, whether human or divine or something else, is this the end of their journey?

In the near future, America is falling apart. Chemical warfare has robbed many of its people of their memories. Memories, essentially identities, are stored on phones. Without their phones, these people will sit and let themselves die, not even remembering that they need to drink a glass of water. The country has become the United States of Amnesia and it is about to get even worse. 16-year-old Otty and her friends have created their own private internet network, a support network, using a technology that isn’t controlled by the eSpires that tower over the land. Agencies want this technology and Otty and her friends must endure a dystopian hell.

Adam Roberts is a master of intriguing science fiction with big ideas and themes. His books also have the most beautiful covers! Purgatory Mount is no different. The novel is in three parts, with the central and longer story of Otty and her friends sandwiched between the far-future story set in space. I loved the opening on an alien world and then we moved to the near-future USA and I was completely captivated by the young Otty. She is a marvellous creation, a living, breathing teenager who is essentially vanished by the authorities. All she has to do is remove their phones, disconnect these bullies from their memories, but it’s almost as if she doesn’t want to do that. There is a decency about Otty that I loved. I really felt for her in her moments of fear and isolation but she is so clever and resilient. The world around her is in such a terrible state but with Otty around it’s difficult to give up hope entirely.

The dystopian American world is vividly imagined and portrayed. It’s recognisable. It’s only a step or two away from where we are, which makes it all the more believable and frightening. The end of the world seems so close and yet, when we are with Otty, it feels like this can be avoided.

One of the things I absolutely love about science fiction is that I can thoroughly enjoy a story, be amazed by its vision and wonder, without necessarily having to understand all of its ideas. I don’t need to understand it entirely to be in awe of it. This is the case with Purgatory Mount. Its two threads do join together and I like very much the ways in which they do. The past influences the future. It moves it forward, or in other directions. In the afterword, we are reminded of paradise lost and paradise found, the circles of purgatory and hell. I have read Dante but that certainly isn’t necessary to find oneself immersed in this tale of sin and atonement, humanity and the divine, identity and confusion.

Adam Roberts has always been so good at creating female characters and Otty is one of my favourite fictional characters in a fair old while. I adored her while fearing the world she lives in. I did prefer her part of the novel despite imagining, at the beginning, that I would love most the far future story in space. This is possibly because Otty is far easier to relate to than the entities of the future, however intriguing they are. The best science fiction entertains and dazzles me while also making me think. I’m reminded of the author’s The Thing Itself (I loved that book!) and I’m going to be thinking of Purgatory Mount for quite some time. And that cover!

Other reviews
The Thing Itself
The Real-Town Murders

Adam Roberts’ work often has a big concept upfront: Snow (what the snow just keeps falling); By Light Alone (what if people could photosynthesise through their hair); Gradisil (what would orbital habitats be like if they organised as a country). So...this opens on a generation starship. Fantastic, Roberts’ take on this trope. Then they arrive at their destination pretty damn quickly, and there’s a Big Dumb Object waiting. Great, Roberts’ take on the inscrutable alien BDO. Hold that coffee. We’re winding back from the far future to around ten years from now.

The story-within-a-story takes place in a US where the worst 2020 predictions of the death of democracy, informal warfare, and gun-nuttery have progressed ten-fold. Which is in many ways a shame as the elements of Roberts’ post-Trump apocalypse feel less original than the first far future section of this novel. Weaponised neonicotinoids, iphones plugging directly into people, artificial intelligence, shadowy and paranoid government agencies, malware, VPNs…it’s a convincing mix of horrors, but not quite on the level of On (idea: what if gravity operated at 90 degrees).

This is not to say that the central section of Purgatory Mount is not a satisfying read. It is. The protagonists, chiefly 16-year old Ottie, are a likeable bunch and their struggles to survive as the US falls into civil war are told with an urgency that will have you racing through this book. It’s just that teenager-in-a-dystopia is a well-mined vein of fiction right now, and Roberts’ story is well-told without being as original as some of his other work mentioned earlier.

We return at the end to the far-future in the final section of the book - where he does connect his two stories - and Roberts’ concerns with revenge, guilt and atonement surface more explicitly. There are references to many belief systems including the Greek gods, medieval Catholicism, cargo cults,the singularity, and post-humanism. The abrupt gear-changes continue as the final resolution is more to do with arriving at a philosophic position than resolving or explaining the plot. Lots to enjoy, and even an postscript explaining some of his thinking, without this novel cohering into an entirely satisfactory whole.

Adam Roberts, Adam Roberts.... I'm sure I've read some but... Three pages in when the ultra advanced humans with generationally relativistic time awareness in their iceberg spaceship go to visit a giant mountain on a planet which they have whimsically decided to name after Purgatory in Dante's Inferno I remembered. Who else melds classical allusions with diamond hard sci-fi but the writer of Hyperion? I loved Hyperion, but my mileage on the four books definately wavered. Same too with Illium et al. So once I twigged, and very much enjoyed the opening chapter setting up potential tales class warfare between the humans and their sentient livestock (Pygs, which may be short for Pygmies which can be taken a number of ways), I was set to have my mind stretched in the ways he had done previously.

And then suddenly we are on Earth. Near future America. A civil war is brewing between MAGA factions and the liberal cities (California secedes at some point). We are with smart kids in a run down Philadelphia, who have somehow angered the authorities and will be picked up by them. And this is the lions' share of the book. The hard conceptual sci-fi is shelved for this slang ridden first person near future war scenario. I couldn't for the life of me see the connection. But that was OK, because whilst I liked the framing story, I really liked this Philadelphia story. Because it is Roberts, I couldn't help but think about the book as a Trojan horse. Was the trip to Purgatory Mount the trick to grab the kind of sci-fi reader who doesn't want politics in his sci-fi thank you very much, and thrust them fully into a gripping story of governmental abuse, private prisons, torture and refugee displacement? If so, job done. There is a stretch of Purgatory Mount where our protagonist Ottoline is arrested, tortured, left in solitary, moved to an inappropriate prison, released and becomes part of a a group of displaced people shot upon and bombed which was compellingly real. Its odd thinking about the political moment the US is currently in, and how even a month after the attack on the Senate this all feels a little far fetched, and yet that passage - even when pinched by mild absurdist satire - conjures up a parallel empathy for other displaced people. There is a run around with another of the kids which is less successful (showing a successful escape after showing how harrowing it is the be trapped in the system leads to diminishing returns), and then we reach the science fiction point of the body of the novel. In itself a strong idea, but not one that links so well to the far future and Purgatory Mount, which we return to for a literal culmination of the Dante plot.

I am torn on Purgatory Mount, which is usually my response to Roberts. Yet again, when he is good he is very, very good, and the strength here is that empathy in the captivity section. I like the framing device as its own piece but I don't think they link anywhere near as thematically as he does. Minor niggles as well but I can't see any group of American teens, no matter how nerdy, naming themselves after an Enid Blyton book, and that's before we get to the biscuit barrel - cookie jar if you have to have one. Minor issues aside, I'd take this for the novel inside the framing device, and the framing device as an equally interesting short story. And whilst the ambition is still there, like I have thought before with Roberts, stop letting the formalism or the allusions get in the way of telling the human (sentient) story.

[NetGalley ARC]

It started a bit like Clarke's "2001: A space odyssey" reloaded, meaning we have a megastructure on a faraway planet, and we also have hal. A crew of five enhanced humans are on the way to research this mountain, which doesn't seem to be natural. Up until 20% my interest gradually grew, and I couldn't wait to see what is it with that structure. I've built up scenarios, waiting to see which one will materialize.

Then suddenly, the story shifts 180 degrees and we find ourselves in a raging civil war which devastes the United States. We follow a 16 years old geek girl and her friends, which are hunted by two different suspicious agencies for something which apparently can change the course of war.

Then in the last 20% we are back in space, on that faraway planet and its misterious mountain.

Two entirely different stories, which at some point do have a minor connection to bind the space story to the dystopian one in the middle, but not the other way around. And it was not enough to relate the two to a satisfying conclusion.

I can't give more details without spoiling the ending, all I can say is that the climax was not there for me; the journey was not enough this time.

However, the premise of the first story was great; too bad it was not properly developed. The middle story was better from this pov, and I got really surprised by the twist which I did not see coming. I especially appreciated the mocking of smartphone addicts; it's bitter and funny at the same time. I think it could have been much better as a story on its own, because it has nothing to do with the other.

But this is Adam Roberts we are talking about, and his works are never what appear to be. As much as I love his articles and reviews, I just can't not feeling dissapointed by this book. The philosophic musings, the references to religion, Dante's works mixed with Middle Earth's hints were hard to process. It's a social and philosophical allegory disguised as a sf story, and for readers which like philosophy more than science, it could be a more appealing read than it was for me.

This is a book of two stories and is structured into three parts.

The first story which takes up the first and last part of the book is about a crew of five that set off from Earth on an interstellar ship to investigate and study some unusual terrain on a planet called V538 Aurigae. What they find is an empty planet and a large scale structure that resembles the mountain of Purgatory as described in Dante's Divine Comedy. I found this part interesting but complex.

The second story which takes up the middle part and the bulk of the book is based in a near future America, a country in turmoil and disarray. A group of teenagers who call themselves the Famous Five develop a new private internet that they alone can access and control. The five find themselves at the center of unwanted attention by various agencies who are ruthless in their pursuit of stealing this new technology. This part of the book was less complex and an easier read, I was reading into the early hours of the morning unable to stop until i had finished it.

I have to be honest and say I didn't see the connection between the two stories immediately and I found myself re reading the 1st and last sections of the book for a second time. Overall Purgatory Mount although complex in parts is an excellent read and I would recommend this book .

This is a complex novel, that combines two very different stories which on casual inspection appear to have very little to do with each other. Or do they?

The title should clue you in that the novel takes some inspiration from Dante’s classic poem, but it also becomes clear early on that it is also in dialogue with classic SFF - there’s speculation about space elevators followed a few pages later by a namecheck for Arthur C Clarke, gullible misheard as Gully Foyle, and a frequent refrain of “the eagles are coming”. This idea of the past being inherent in the modern is also expressed in the preoccupation with original sin, memory and atonement that saturates the book. It’s also interesting that of the two story strands, the one set earlier in the timeline has a distinctly YA feel, while the later is slower, more philosophical and more adult (to use a poor but easy term). You could tease out something here about how we grow from youth to age, and go back once more to the idea that our past defines our now - without being too spoilery, the reason why characters in the later strand are in the positions they are is embedded in the earlier story.

I might be making it sound very dry here, but it’s worth noting that for all the philosophical musing of one strand and the convulsive violence and upheaval of the other, the novel is told with a lightness of touch and a delight in wordplay and puns that make it a very smooth read. There are frustrations - certain mysteries are left dangling - but overall this is very readable and very thought-provoking. Recommended.

This is not sci-fi. This is science fantasy.

Overall, it was an enjoyable two-story arc story and read. I enjoyed the first part of the story. The adventure the characters went on was far more interesting than the second half of the book.

In the second half, I mostly didn't like many of the teenage characters. Though, yes, I understand the reasoning behind having such a younger, teenage cast lead the story being told. Tech is beyond being a crutch, perhaps mirroring the current state of the world (some parts of the world, at least).

3/5

Purgatory Mount is a complex and philosophical science fiction novel one would expect from a professor of English literature. It’s also a terrifying image of near future USA and an imaginative vision of far future of the humanity.

This is not a simple read. It presupposes a working knowledge of Dante, medieval Christianity and modern Catholicism—particularly the ideas of original sin and purgatory—the pantheon of ancient Greece, and the Lord of the Rings. It’s not an easy concoction and it doesn’t always work. This could be, as the author tells in the afterword, because the elements from the Middle Earth had to be replaced with the Greek pantheon for legal reasons, but I don’t think it would’ve made a great difference for the reader. What we have is non-Christian entities philosophising about Christianity, which doesn’t make for an easy first chapter.

The story is told in three parts that, according to Roberts, reflect Dante’s vision of afterlife: hell, purgatory and heaven. Of the three, hell and heaven exist outside time, and the purgatory in the temporal world, i.e. is subject to change. This isn’t immediately obvious to the reader—or even after reading the afterword—but time does play a role in the story.

The first and last parts take place in far future on a generation ship orbiting a dying planet that features an enormous tower. It has lured five entities forty lightyears from earth to study and profit from it. They call themselves human, but they have a lifespan of tens of thousands of years, bodies that are more machine than organic, and the ability to bend time to their will. Consequently, they consider themselves gods. They are named after Greek gods Zeus, Apollo, Dionysius, Hades and Pan, although the omniscient narrator of their chapters is quick to point out that the names are only for the reader’s benefit. However, apart from Pan, the names don’t really reflect their characters—they don’t really have any personality—and it wouldn’t have made any difference if they had been named after the wizards of Middle Earth as was the author’s original intention, or with numbers even.

Living on the ship are people who also think of themselves as humans. They have short lifespans of maybe forty years, and they’ve been living on the ship for generations. They have a complex culture and religious life that revolves around the gods running their ship, and no true understanding of why they are on the ship—or what is a ship—and what their purpose is. For the gods, they are food. The gods call them pygmies, and the few descriptions of them gave me a notion that they might be some sort of evolutionary form of pigs. Their entire existence becomes under threat when they are told that they have reached the journey’s end. Is it the end of the world? From among them rises B who is the only one curious enough to find out what is going on—for what good it does to him.

The middle part, which is about twice as long as the other two, takes place in the near future USA. It has descended into a civil war between various states, government agencies and private militias, with no-bars-held warfare. It’s technologically far more advanced society than one would suppose of 2030s. There are some interesting innovations, like a system for uploading operational memory into iPhones, which is mostly used for helping people suffering from a grave memory loss due to chemical warfare. And the country is riddled with enormous towers, eSpires, that no one knows what they are for.

A group of teenagers, fed up with the government surveillance, have developed their own private net. But their system holds a secret, which all the warring factions want and will do anything to get. We follow Ottoline who is captured by a nameless government agency and plunged into a journey of survival through prisons and warzones. The secret Otty and her friends are trying to keep took me by surprise, and not necessary in a good way; a bit more information would’ve gone a long way to understanding how a sixteen-year-old would be able to withstand everything that was thrown at her. Once the secret is out, it takes over and the world as Otty knows it basically comes to an end.

I read the entire book trying to figure out how the two stories connected, and failing. According to the afterword, the book is about memory and atonement, which … I really don’t see. The loss of memory plays some role in the middle part, but mostly on the background, and it doesn’t guide the actions of the characters in any way. The pygmies have their collective memory, which has corrupted over the long journey, but it doesn’t really play any role either. And the gods remember everything.

Atonement is even more difficult concept to accept, because as far as I can see, nothing is atoned. The purgatory itself is a system of atonement, but for all the talk about Dante and afterlife, none of the characters really go through the purgatory; Otty hasn’t even done anything that would require atonement when she goes through her ordeal. Pan has a crisis of conscience when it comes to the gods’ treatment of the pygmies, but they don’t really atone either; they abandon the pygmies to their fate.

Instead of atonement, there is revenge: Otty’s collective revenge on humanity for harming her friends and Pan’s revenge on the other gods for disrespecting them. Otty uses an AI as her instrument of revenge, Pan uses the pygmies. If either of them atone their actions, it happens outside the narrative.

What really connects the two stories is the tower. Not as an idea that has travelled lightyears to inspire Dante, as Pan suggests, but a different biblical concept entirely: the tower of Babel, (human) hubris and inevitable downfall.

The towers, eSpires and the Purgatory Mount, don’t have an active role and we never really learn anything about them, but they are why the events of the stories take place. On earth, the fear that the towers spy on them causes the teenagers to build their own network, which eventually leads to an apocalypse of sorts. On planet Dante, the tower is the reason why the ship is there and the cause of the strife between the gods that leads to Pan’s revenge. And it may well have been the downfall of the people who built it too, leading to the planet dying.

Purgatory Mount is a complicated book, but it’s not difficult to read. It’s perfectly possible to enjoy the two stories for what they are without trying to find connections between them. They’re slightly uneven in scope, but both are interesting and good. I liked Otty and B the pygmy who is caught in Pan’s revenge, and if the gods were pompous and not very approachable, their end was satisfying. And for those readers who like to challenge themselves, this is a perfect read.

I was kindly given an ARC of this book by NetGalley in exchange for a fair and honest review.

IRobot vibes! 3.5***

This book was an enjoyable and easy read. I found myself flying through the pages and enjoyed the writing style.

There are two stories in this book.

The first story features technologically advanced humans, that are godlike, lording over other species (and talking cows)! They go on a quest in a giant spaceship to investigate an alien structure. I really liked the names and personalities of these characters but found myself wanting to know more. It was such a short part of the book overall but I felt it was the most interesting part. I wanted to know about their lives on Earth, their ideals, life on the ship etc.

In the second story there's not too many characters which keeps things nice and simple. The characters are believable and the world itself was set in reality. This is a Dystopian world set in a not too distant future where technology has taken over even more of our lives. There's relatable references to covid, Donald Trump and Taylor Swift which grounds you as a reader, giving you something to relate to.

In this story a group of teenagers have created something the government wants. It features millions of people, who are essentially walking vegetables, who if not literally connected to an iPhone cannot function as a human being. Poisoning of the brain has become weaponsied and the new warfare.

The story was interesting but at times the immaturity of the teenagers was a little frustrating as an adult reader (just listen to the people not killing you?!) I wanted to know more about Wesson and the aftermath of their creation. It would have been especially good to hear how story two's world become story 1. I'd have loved to know how that happened as it felt that the 2 stories were just a bit too distant for me.

All in all an enjoyable read.

The eagles are coming!

The eagles are here!

Adam Roberts is one author I'll always, always take time to read and I'd been sp looking forward to Purgatory Mount. I thought I knew what it was going to be about, and it was that... but also it wasn't, it turned out to be something much bigger and very different and thoroughly ramified. It does, though, rather defy a neat review. I could just say, buy this, and stop at that but I really want to persuade you, so let's try that.

Opening as a city-sized interstellar exploration ship, the Forward, arrives from Earth at a distant planet, V538 Aurigae - gamma, we seem to be in hard SF territory with a description of the long voyage, the peculiar emptiness of space in the interstellar "Local Bubble", the ice-encrusted ship itself (the ice provides both a shield and fuel), the crew - who are able to alter their perception to live faster or slower, surviving the generations long (for their livestock) voyage - and the mysterious alien artefact that has drawn Earthly attention. No, not an obelisk - an immense spire so high that it soars beyond the planet's atmosphere (indeed, beyond the original, deeper atmosphere long eroded by the local star).

What is the spire made of?

What is it for?

Where did the makers go?

Just as we might think we know what's coming - Roberts will describe the crew's exploration and tease out these mysteries - he knocks the reader sideways by adopting a different genre, the near future thriller, and location, the USA a few years from now. That country is on the edge of civil war ('The problem is - there are plenty of people real keen to shoot their guns and run around in combat gear'). Ottoline (Otty to her friends, who call themselves the Famous Five in a reference which I suspect isn't to be found in the cultural life of the typical American teenager, now or near future) is fleeing from the adults. From government law enforcement. From the gun-toting militias. From a mysterious third faction.

The description of the rending fabric of a modern state is terribly compelling and oh so convincing, particularly in that there isn't an overnight collapse. Otty sees a bureaucracy staggering, still trying to function, but losing its coherence and purpose. Even at the level of the combat, the increasingly dislocated refugees, the writing is terrific (in both senses) and remembering the turmoil on 6 January, I couldn't help compare this vision of a USA that has begun eating itself to that coverage on CNN of the swamping of the Capitol by an army of grotesques.

That conjunction, which couldn't have been foreseen, makes this book seem prescient in detail, seem predictive, to an extent that may distract the reader from what I think is more fundamental, and intended, a sort of moral prescience which becomes clearer towards the end. But still, the idea of incipient civil war, of rage and destruction spraying in all directions, the urgency with which Roberts captures the violence, the unholy beauty he finds - look at the description of a coach being blown up ('Boom, boom, shake the room. Crush, crush, flip the bus') - all of this makes the book absolutely, grabbingly, compulsive.

Roberts pulls out all the cultural stops in characterising this process, from the explosion 'like a colossal door being slammed shut somewhere in Hell' (yes, we know what that would be) to the queue jumping mob ('wearing Old Glory jackets and red MAGA caps') who try to barge onto the bus to the sharp eyed lawyers and journalists who prowl through the ruins trying to make a turn from the chaos. It's a purgatorial landscape for a sixteen year old to find herself traversing and there are no more answers as to why all this is going on than there are to why Otty is being targeted. We see a limited explanation from one character, that it's all about the money (in New Model Army, Roberts posited an almost cheerful, open-source approach to urban warfare, with some idealism driving it, here the mood is a great deal darker, more despairing).

I started reading this near-future section thinking, what's this - when do we get back to the Forward? - then found myself more and more drawn by the hectic story, the scrapes, the sheer guile and courage of a young woman whose life has been upended. We don't know, for most of the story, why Otty is on the run. She's far too canny to reveal that, to us or her interrogators. But her pursuers are clearly bad, tainted in some sense by an association with the chaos and destruction raining down and slowly, surely, they push Otty to a desperate place and to an act with unforeseeable consequences.

We do return to the Forward again, eventually, for a final act in which the connection between the two timelines is made clear. Otty's experiences turn out to be foundational to the existence of the Forward and its crew, but also to the position of others on board - to the creatures known as "Pygs" who worship the Crew as gods. And they drive the actions of both in a moral sense, Roberts invoking the concepts of Heaven, Hell and Purgatory - sidestepping the hard physics question of how that incredible, planet-topping spire was built and how it stands up for the more interesting question of what it means and what that means for those who have travelled so far to see it.

That feels like a place I could stop - Purgatory Mount an utterly compelling book, fiercely intelligent and unconventional SF rife with ideas yet completely approachable and fun to read - but I think I also have to point out a couple of further things. First, Roberts' writing is glorious, subtlely varying to fit its subject - for example look at the down to earth, dryly humorous, opening section, even amidst all that science-y exposition, or the beauty he often evokes ('the sky was starting to blush strawberry and yellow-orange, with bars of luminous cream-coloured horizontal shine layered over the top of it'). It can also be mischievous, or mischievously inventive, as with the word 'sidegoogling' which occurs a few times (I NEED that word!) or references to the Forward's 'hal', its AI. And how about 'her heart was beating in her chest like Animal from the Muppets playing the drums'?

Which reference brings me to the second thing I wanted to mention here (and then I'm done, I promise). This book is drenched with Lord of the Rings references and comparisons. Most broadly, there's the whole device of telling us, as Roberts does in several places, that names or cultural references used to describe the ship or its crew have been translated into terms we can relate to from something utterly strange that we wouldn't get. (In fact the most blatant example of this didn't, as the author tells us in an afterword, survive copyright issues - he wanted to give the five members of the Crew the names of the five wizards from The Lord of the Rings and indeed Pan, the one we meet most, 'a figure gifted with magic (in the Clarkean sense of the word) and given responsibility over beats, birds and plants...' would make a fine Radagast). There is also lots of detail, such as tree trunks which 'shuddered and moaned like Ents' at the force of an explosion, way bread, or all those references to eagles - The eagles are coming! The eagles are here! - but also 'Somebody would come to rescue her and she would fly away on the back of a Johannine eagle'. The latter bridges the gap between Tolkienish references and the Christian ones behind Purgatory Mount, with its themes of offence, of sin, redemption and atonement.

In short, this book is a glittering achievement, Adam Roberts in full splendour giving us a novel of ideas, of fun, of beauty. Go and get it.