Thank you Netgalley and the Publisher for this ARC in exchange of a honest review.

“A Letter to the Luminous Deep” by Sylvie Cathrall is an enchanted fantasy set in a house built under the sea that follows the E. and Henerey’s story and tries to uncover the truth behind their disappearance. The author doesn’t merely describe this journey in the usual way, it’s entirely narrated through letters, diary entries, notes, etc… And it turned this book into an actual adventure!

E.’s sister, Sophy, is a prodigious Scholar and after her retirement she undertakes a correspondence with Henerey’s brother, Vyerin, in order to discover something more about their siblings’ premature departure. In grief and in the mutual need to heal, they will uncover some uncanny secrets both about E. and Henerey, but also about the world they think to know.

First of all, the most intriguing aspect of A Letter to the Luminous Deep is the way this story is told. An epistolary novel that takes its time to let the reader get personal with the characters and the world they live in while building true and endearing relationships.
This novel extends beyond the romantic relationship in its usual sense. On the contrary, we encounter many types of love: the unexpected and needed friendship of Sophy and Vyerin that grows hand to hand; the love that arises between E. and Henerey written in their letters; the boundless sisterly love shared between Sophy and E.; the beginning of Sophy’s love story with her future wife Niea; the unconditional love for knowledge; and so on.

This novel leaves nothing to chance and it’s striking how well-crafted these relationships are. I was afraid that the absence of proper tangible conversations or any kind of moment between the character as we readers are used to read could affect my reading experience or lack of pathos. Obviously, it wasn’t the case. The author’s style turned the book into a long reminiscence and investigation that can’t help but involve the reader.

E. is the main character of this novel. She’s a 27-year-old woman affected by OCD, thus she spends her life in the Deep House, trying to overcome her fears. E’s affliction, such as all the other mental health conditions affecting other characters, are well portrayed. The author’s way of writing helps the reader to understand and feel for them.
Personally, E.’s point of view in her letters, her struggles, but mostly her strength made her become one of my new favourite characters. E. may seem fragile and vulnerable, but throughout the book she always tries to overcome her worries and intrusive thoughts.
Henerey’s letters played a great part in helping her and I loved how they both assisted each other in fighting their inner battles. Their relationship feels so genuine and sweet!

I also loved reading about Vyerin and Sophy, how they mourned together while attempting to comprehend what had occurred to their siblings. They slowly started trusting each other, becoming friends and taking the best from that unfortunate situation.
Another important part of the plot is Sophy’s journey to explore the Reef in the deepest part of the ocean. I enjoyed discovering more about the world and the mystery that was becoming murkier and gloomier as the plot proceeded.

Not only the Deep House was interesting, but also the entire world building. It focuses on the sea, what it hides after the so-called Dive that brought the people to live in a world made almost completely of water, and which creatures swam in its depths. Scholars seem to rule over this universe and numerous branches split them into different fields of studies.
The world building isn’t as deepened as I hoped it to be, but it was certainly a difficult task for an epistolary book. The author focalised on the vibes by building up an atmosphere that would enhance the reader’s curiosity and involvement.

Something occurred to my mind: if there were so many innovative technologies that could prevent you from dying from the high pressure of the sea or that aided you reach the deepest part of the ocean, they why there was only epistolary correspondence? Am I missing something out? I feel like in certain aspects it seemed a rather advanced population, yet on other points their way of living seems quite rudimentary and “basic”.

The novel ended abruptly, hinting for a sequel and I’m so happy to meet these characters soon. And yet, the end felt far too rushed in an unjustified way, leaving the reader with a lot of unanswered questions that will surely be addressed in book two.

Let me say that A Letter to the Luminous Deep turned out to be one of the most unexpectedly beautiful release of this year. A remarkable debut easily lovable if you like Emily Wilde’s Encyclopaedia of Faeries or Divine Rivals.

4.5 stars
Told in letters and messages, A Letter to the Luminous Deep had me hooked from the very beginning and before I knew it I had devoured half the book in one sitting. I quickly fell in love with Cathrall's writing style and how the world was built through these correspondences.

I also think I'm now a sucker for light academic romances and need more of them in my life! The relationship between E and Henerey was just so beautiful and I loved watching it grow and blossom as they exchanged letters. The connection they have is just perfect and I quickly grew to adore them. I really related to E and her struggles with her mental health. Suffering from agoraphobia and anxiety myself I instantly connected with her and how she was feeling a lot of times throughout this book. I also really loved getting to know Sophy and Vyerin and the friendship they create in hopes to uncover what has happened to their siblings.

Honestly this is a book you should go in somewhat blind to so that you start to uncover the story alongside them. It was such a beautiful, lyrical debut and I cannot wait for the next book!

Thank you so much to NetGalley and Orbit for sending me a copy of this book in exchange for an honest review.

Thank you Little, Brown Book Group Uk and NetGalley for providing me with this arc in exchange for my honest review.

I have spent 2 weeks with this epistolary adventure. A light academia and a delight to read, both comforting and fascinating.

Saying that I am excited to read the sequel is an understatement. I am beyond excited because this unique, meticulously crafted fantasy with the most beautiful slow burn romance, has swiftly become a favorite and I cannot wait (I honestly just want it now) to dive ;) into what I think will be an even more wonderous, fascinating sequel and be reunited with these intriguing, charming and kind characters.

I almost forgot to praise the incredibly beautiful cover! I cannot wait to receive my special edition by Fairyloot which will no doubt be a treasure to display!

I have always been fascinated by the underwater world and thoroughly enjoyed my academic years and reading about a character who actually lives in a house underwater, part of a society that once lived in the clouds and now lives mostly “on top of” the oceans (there’s barely any landmass) was incredibly exciting to me. Some of the other important characters explore unknown depths or are scholars in somewhat safer environments, a captain, an architect and an artist.

This book brims with mysteries, both solvable and unsolvable and they are fed to us in bits and pieces as they are to the ones eventually trying to solve them.

I am going to end this review here, it feels like the right thing to do as I enjoyed not knowing much about this story when I had the privilege to start reading it well before its release date. I am forever grateful that I got the chance to read this book because it contains so much I love about the fictional and real world.

If you get the chance to read this unforgettable epistolary adventure, which I highly recommend, I hope you enjoy and find as much comfort in it as I did!

This book was beautiful, charming, and so, so special!

~E. Cidnosin spends her days in the Deep House, passing her time looking into the reef outside her window and observing different life forms. One day, she catches sight of a type of fish she does not recognise, which prompts her to send a letter to Scholar Henerey Clel describing the odd creature. This will be the start of a special relationship between the two, which develops in the sweetest, most natural, and innocent manner. Through their letters and encounters, they discover a mystery within the dark waters outside the Deep House, but tragically disappear after a seaquake destroys the underwater house.

A year later, Sophy, E.'s sister, and Vyerin, Henerey's brother, start a journey in which they share their grief over their loss, as well as letters, sketches, and field notes left behind, which may hold the key to their siblings' disappearance.~

I need to start by saying that I had no idea what I was going into when I started this book, and I think this made my reading experience so enjoyable! The story is told through letters between different characters, some field notes, personal diary entries, and news publications. At first, I was a bit taken aback by this, but I quickly found myself really enjoying the dynamic and pace of the story. I felt that the world building was done fantastically well through descriptions found within the letters, and did not feel as if I was missing anything at all.

I loved how well written this book is: the characters' different personalities shone in their letters, and the relationships between them developed in such a natural manner. The letters between E. and Henerey really showed, at first, their admiration and respect for one another, and later on, their affection, trust, and love. I really enjoyed how the author very sensibly portrayed the challenges of OCD and social anxiety through E.'s character.

The relationship between Sophy and Vyerin starts through their shared grief, and slowly evolves into a very special friendship. The love each of them had for their respective sibling can really be felt throughout the story, as well as the affection they develop for one another.

I really don't want to spoil the story and I think it's best to go in blind. It was so different to anything I've read before! The world building, the premise, the whimsical and Victorian-inspired writing, and how the story is told through letters... it was such an enjoyable experience to read this book, and I can safely say it's a new favourite! It deserves all the stars, and I cannot wait for the sequel!

Thank you so much to NetGalley, Orbit Books UK, and Sylvie Cathrall for the opportunity to read an ARC in exchange for an honest review.

Thank you to NetGalley and to the publisher Orbit for the digital ARC, it has not affected my honest review.

Although this book sounded absolutely perfect for me I found that the epistolary style meant that I had little connection to the characters because some of them had similar sounding voices.

This novel was delightful. It made me want to write letters again, even though my ability to keep in touch with anyone is woefully bad. I loved the style of it. I loved the plot. And the characters did a great job of keeping me enthralled even when not much was happening.

I will say, this is not an action book. The plot is very slowly built and a lot is done in hints and suggestions, so you pick up on ominous things as you go. While I actually really enjoyed this (because it really built up tension)it did lull a bit in places and it’s not for everyone and I think you have to be in the right mood for it.

Most of all though, I loved the world. This Victorian-esque society full of queer scholars who kept up massive amount of correspondence to everyone they knew while living on boats or deep underwater? I loved it. It was this odd mix of sci fi and historical that I just wanted to know so much more about.

I hope there’ll be another book. I feel the ending left room open for one. I would definitely like to go back to this world and find out more about what happens next!

This was such a good book and one I did not expect to like due to the way the story was told.

I’ve never read a book like this and I was totally into it
Could not put I down

✨ I wish that while you were here I could have had the opportunity to tell you how luminous you are✨

🐟 A Letter to the Luminous Deep is an epistolary novel and precisely because of its structure it turns out to be very unique: Through letters, diary excerpts, and drawings exchanged between Sophy and Vyern we will discover the cause of the mysterious disappearance of their siblings E. and Henery, whom we will see become friends and slowly fall in love.

🌊 I admit that I struggled initially given its very particular and descriptive structure but ,once I got used to it and paid attention to the senders and receivers of the letters , it became a magical and poetic read! Through the letters we come to know the thoughts, fears,hopes and adventures of the characters making them all too real, especially E. with his anxiety. In short, through pen and paper we are led inside the book to experience the story firsthand along with the characters.

💌 Reading about E. and Henery took me back to the time when love blossomed gently, slowly and spontaneously. If I loved the story of E. and Henery , the relationship between Sophy and Vyern born out of grief and sorrow and blossoming into friendship literally warmed my heart.

✨ I started this book because of the cover and ended up devouring it in two days finding it brilliant, gentle as a daydream. In fact I found myself enchanted by the marine setting and intrigued by the mystery part which left the foundation for the next book. As a genre I would call it an academic light, so if you are a fan of Emily Wilde you will love it!

This is such a gorgeously written book! It's almost poetic language, the light academia vibes and the interesting world building is what sold me on Sylvie Cathrall's debut novel. Epistolary novels are tough to pull off, and I admit that they're very hit or miss for me. I actually enjoyed this one and think Cathrall did a great job.
At its core, this is the love story between two scholarly people that bond over their love of knowledge and discoveries. It's told entirely via letters and documents, mostly the first. These letters are both ones sent by the two lovers to each other and to their respective siblings, and ones written by these siblings who are trying to find out what happened after the alleged tragic, and rather mysterious, death of the couple.
I do have to say that the story drags a bit up to about 60, 70%. Then the more mysterious aspects of the story are put more to the firefront and things get more interesting. I wasn't entirely sold on the love story, mostly because it happened very very fast (the characters acknowledge this themselves, though) and I actually would have loved more development of feelings between E. and Henerey - instead we get a lot of back and forth and relationship building between their siblings. I also felt like the four main voices weren't distinct enough. They all kind of sounded the same with minor differences.

The really slow pace with the most exciting aspects of the whole book all cramped into its late chapters and the samey voices of the characters are why I eventually chose to give this 3 stars, although it's more of a 3,5 for me. Also, I thought this was a standalone when I requested the arc, which was what I expected then while reading - not the greatest surprise, but I will most likely pick up the next book for the very atmospheric world and the really cool lore and mystery!

A Letter to the Luminous Deep is an absolutely beautiful light academia cozy fantasy read. If you enjoyed Emily Wilde's Encyclopedia of Fairies or have ever wanted to read a book that feels like Palamedes and Dulcinea's letters from the Locked Tomb must, you will love this.

There is a beautiful epistolary romance that will make you swoon, as well as two queer protagonists, one of whom we also get to see fall in love. There is a lot of kindness and familial love. There is a mystery that at times did scare me a little and kept coming together beautifully. There is a lot of scholarly language that made me feel deeply immersed in the story and as if I was personally reading a report on some beautiful and fantastical mystery.

And very importantly to me personally, there is incredibly well done OCD representation that draws on the author's own experience. It is so rare to see OCD rep in fantasy and I loved and empathized with E. so deeply. I highly recommend you pick up this beautiful story and cannot wait to unravel the mystery of the luminous deep in book two.

Headlines:
A fantasy world under the sea
Two awkward people
Connections through letters

There's so much uniqueness in this story, this world under the sea, coral reefs, sea creatures and of course the societies inhabiting. The world seemed futuristic possibly to our world and vague references were made to a previous civilisations and possible climatic issues. That said, the world of this story was visceral, colourful and kept my imagination busy visualising.

The story was told in epistolary format, with a somewhat formal tone. That was a little jarring initally but I did settle into the format and the letters got more informal as time went on. There was a mystery afoot in this story, some missing main character and siblings of the missing E and Henerey also conversed through letters in their grief and search for answers. I did have to concentrate quite hard initally to be certain if this was a letter between E and Henerey or a letter between their respective siblings.

The characterisation authentically wove in some mental health issues with a rather anxious E and a contrast in the support and understanding or lack of she got from her siblings. Siblings on both sides were queer characters. For me, Henerey and E were a delight and while the sibling brought key parts to the story, I was always eager to be back with those two MCs.

I'll definitely be reading on, I need to know the what next. Will the next book be epistolary, I wonder? I can't see that it would need to be but who knows!

I both read this and listened on audio for larger parts and the narration was very good, assisting with the POV changes through voice.

Thank you to Orbit Books for the review copy.

This book was unusual, but in a very good way, I liked it a lot! It's an epistolary novel about siblings and couples, about loss, mental health and academia, set in a world where there is only very little land and most people live on (or in) the ocean.

Together with Sophy and Vyerin we discover the fates of their lost siblings, while reading their correspondence from before their disappearance. This plot structure worked very well for me, I was intrigued to find out what happened to them and at the same time loved to see their love and friendships respectively develop through the letters and notes they send each other. Usually I tend to miss direct conversations and actual meetings in epistolary novels, but this one managed to bring across all the important feelings and thoughts beautifully.

The writing itself was also amazing, there were various distinct voices transported in the letters and the characters really came to life through their writing. E. and Henerey have such a beautiful writing style, rather old-fashioned but in the best way! I really liked it.

The world was super interesting with all its different scholars and vessels and habitats and creatures! I can say that I've never read a book about a world like this and I thought it had the right amount of detail. Some scenes were a little difficult to imagine but that's also due to the epistolary form of this book I think.

Towards the end it was very gripping, though the last few letters were a bit anti climactic, but maybe that was just because I was so tired. Overall I'd recommend this book to everyone who likes to read epistolary novels and slow-ish fantasy set in a unique world.

Thanks to orbit and netgalley for the arc!

I found the book dragging for the first 60 or so pages, and was tempted to DNF due to the lack of progression, similarities in tone between every single character, and minimal world building... BUT after delving deeper, I found myself becoming enamored with the oddities and marvelous mysteries contained within the epistolary form.

Yes, this is a slow book. Yes, you will wonder if anything is ever going to actually happen. No, not everything concludes neatly (far from it, as this is just book one). Despite all this, A Letter to the Luminous Deep is well worth a read. I ended up loving having the secrets unravel letter by letter, and it allowed me to piece together what happened and what may happen in future alongside Sophy and Vy. In fact, I felt exceptionally clever when I thought I'd uncovered what the Structure was only to then have its true nature be even more wonderous. It's not often a book truly surprises me, so I was thrilled by the eventual realizations and the plan to seek out answers.

The storyline is intricately crafted, with hints dropped from the very start so you can look back and collect the evidence much like a Boundless Scholar. The prose varies from twee to poetic, making the characters and their aquatic world slowly come to life as you warm up to their written words.

Even the romances were charming. From courting in the depths to a love that grew from a single letter penned with anxiety and heartfelt appreciation... There is a relationship for everyone to admire here.

While E and Henerey do not have much in the way of face to face interactions, what they share on paper creates a deep level of trust and mutual respect that blossoms into something more. I do hope the next book allows for verbal communication as I would love to see these two working together more!

Overall, A Letter to the Luminous Deep is mysterious and magical (albeit slow to start), and will be a treat for those who like underwater adventures, academia, and a focus on mental health.

I have mixed feelings on this book - and I'll start with the positives!

Firstly, both E and Henery were very compellingly sweet characters, and my favourite parts of the book were reading their exchanges. I wish there had been more of their letters.

Secondly, I found the format of reading a book entirely composed of letters / notes to be an interesting one, and in some respects enjoyed this slow unravelling of this fantasy world and tale.

The downside to this format, especially in reading a fantasy novel that requires world building, is that as this was done through letters - it felt a bit disjointed, and I found myself often confused and not following completely. I actually almost stopped reading at some points as it was almost too complicated as a reading format. I think also as it was building a fantasy world, and the characters all had unusual made up names - and even the measures of time were not 'normal' - added to this confusion.

With all of that being said, I am glad I made it to the end to see what potentially became of E & Henery, and appreciate the complexity of writing such a book in this format!

Many thanks to Little Brown Book Group UK | Orbit, Sylvie Cathrall & NetGalley for an advanced reader copy in exchange for my review.

A Letter to the Luminous Deep sounded right up my street. I loved the title and couldn’t wait to read it. I love fantasy so this book ticked all of the boxes for me. I loved this book, really loved it. Everything about this book delighted me. I didn’t want to stop reading it and leave the world and characters behind. The really liked the way the book is structured, a series of letters between characters as well as journals, newspaper articles etc. I’ve never read a book that uses this structure before so it took me a while to get into. I also like books that use time shifts so I had a great time reading this. I loved it and would recommend it.

Thank you to NetGalley and Little, Brown Book Group for providing me with an eARC of this book!

A Letter to the Luminous Deep was one of my most anticipated reads for this year. At first glance, it hits all of my most favorites. Beautiful prose? Check. An academic (or academic-adjacent) setting? Check. A quirky/misunderstood FMC and a soft and loving MMC? Check.

Separately, I enjoyed pretty much everything about this book. But the actual execution and combination of ingredients just fell flat.

I really enjoyed the POV characters, both E and Henerey and Sophy and Vyerin. I thought they felt well-developed and were interesting.

I also really enjoyed the world and the world-building. I am a huge fan of the ocean and aquatic life. The world this book was written in did very much intrigue me.

And the plot (what bits of it we had) also did interest me. I am curious about what happens next. Admittedly though, I had no idea this was not a standalone work and I wish I had known as it might have tempered my expectations for plot delivery.

But as I said, despite enjoyable ingredients, the final product just didn’t hit the mark for me. If dragged for much of the book, and many of the entries felt as if they were just fluff rather than actual advancement.

This was a beautiful book. I wish I had liked it more.

A Letter to the Luminous Deep by Sylvie Cathrall
2/5 stars
I loved the idea and format of the book but I found that I struggled to fully get into the book. The cover is absolutely stunning and I really wanted to fall in love with this book which sadly was not the case.

3.5 stars (rounding up coz I want the ARC for the sequel when it’s available)
One Liner: Ultra-slow-motion; but beautiful!

E. sends a letter to renowned scholar Henerey Clel after she spies an intriguing aquatic animal outside her window. Soon, they correspond regularly and fall in love. However, life in the underwater world has its risks. When the duo uncovered a mystery, they didn’t know it could destroy E.’s home. E. and Henerey vanish, presumed dead.
A year later, E.’s sister Sophy begins to archive her articles. She contacts Henerey’s brother Vyerin, and they begin to go through the letters and notes to discover more about their siblings and the mystery.
What happened and why? How does the truth change their lives?
The story comes in the form of letters, news reports, and other snippets shared by different characters.

My Thoughts:
Firstly, a huge thanks to an early reviewer. It helped me go into the book with the right expectations (ultra-slow pacing, almost non-existent plot, and a cliffhanger). I’m sure I enjoyed the book more because I knew what it was going to be.
The beginning is intriguing but soon dissolves into a lengthy character-building exercise. While the idea of showing character development only through letters and journal entries is a great idea, it cannot come at the cost of the plot.
I continued to read and read and read and finally, after 70%, saw a ray of hope. Maybe if the letters were shuffled to provide two tracks – one to get to know the characters and another to follow the mystery, we might feel better involved in the book.
The underwater setting is ambitious. It takes time to understand the whole thing, so wing it until you get a hang of it. There are enough details to picture the setting, so it shouldn’t be too much of an issue. Moreover, the technology and stuff used can be compared to what we have, making it even easier to create parallels.
There’s no denying E.’s arc. It is indeed beautifully done. Sophy and others are well done, too, but E. shines just as she should. Henerey is equally adorable. My only grouse is that the plot and pacing needed to be sacrificed for this.
The letters are formal, with many post scripts, dashes, and parentheses. Do I mind it? Nope! That’s how they are supposed to write. It aligns with their professions and backstories. However, I wish the voices were a little more distinct. Giving them each a quirky trait might have helped. On a side note, I have no idea how this would work on audio.
The last section is truly where things start to come together. But it shouldn’t have been left until that point. Strengthening the threads from the midpoint would have worked even better.
Also, sorry, but E. Cidnosin sounds a bit too close to e coli (at least to my brain). It’s a me thing, but I had to mention it. Her full name, though! Poor girl. I understand why she preferred E.

To summarize, A Letter to the Luminous Deep is a character-driven book that sets the stage for the next book while providing snippets of information. Whatever is revealed is my kinda stuff, so I would love to read the next book and see where it goes.
Thank you, NetGalley and Little Brown Group (Orbit), for eARC. This review is voluntary and contains my honest opinion about the book.

Not a book for everyone - it is definitely one of these very polarizing works, but has indeed potential if you are that kind of reader.
The epistolary format, especially when paired with a descriptive, borderline poetic writing style and the lack of explicit action can feel slow paced and can create a disconnect between the reader, the characters and the story line. If the above is not a deterrent, you should definitely give it a try - a scholarly correspondence in a submerged world, a sprinkle of mystery and tender romance all unfolding via letters, articles and diaries entries could be exactly the right mix for that relaxing weekend where you long to get a glimpse of a different place while still sitting on your favorite couch. To me, this was not an “all in” page turner, but more or a gentle, whispered story observed from afar.

3.5 stars.

I've seen this compared to Emily Wilde and I understand the comparison because of the academic context and writing, sober yet moving romance, peculiar characteristics of the characters, and otherworldly mystery. That said, I enjoyed this, but I don't think it's as enjoyable as Emily Wilde and it doesn't have the same whimsy.

This is an epistolary novel, which is what attracted me to the book in the first place. I loooove a good penpal situation and it delivers on that front. I enjoyed getting to know all the characters and the letter exchanges made this very easy to get into and read. The writing style is academic, but it doesn't make things dense. Also, the worldbuilding is very interesting and I loved the underwater setting.

However, I do have a few issues. For one, I don't think this book needed to be over 400 pages long. It dragged on a bit and not much happens for most of it, so that dragging is not justified at all. I skimmed and I didn't miss a thing. This would've been great at, like, 300 pages, and I think a lot of things could've been cut without affecting the larger picture at all.

Also, the characters don't have distinctive voices. If you showed me an unidentified letter from E., another one from Henerey, and one from Vyerin, I would say it's the same person. All characters have different characteristics and I do feel like I know them, I just wish they felt different in their letters because they all express themselves exactly the same way.

Overall, I enjoyed this and I will be waiting for part 2 because I did connect with the characters and I definitely want to know how things wrap up. It was charming and interesting enough, cozy, and made me crave a penpal relationship.