The premise of this detective novel is very clever. It takes place in a version of contemporary Cambridge society with two classes of citizen: monos, who can only remember what happened yesterday, and duos, who look down on monos, because duos not only remember what happened yesterday, but what happened the day before yesterday, too. Both classes make daily entries in their iDiaries and consult these for ‘facts’ about themselves.

When the body of woman is found in the River Cam, it initially looks like suicide, but Hans Richardson, the investigating detective, is convinced it’s murder and sets about interrogating a shifty circle of suspects and their electronic memories. However, Hans has his own secret. He’s a mono masquerading as a duo, so to avoid revealing his true social background he’s under pressure to solve the case in 24 hours, before his memory fades and he can no longer make new mental connections.

As I say, this is a smart concept, but unfortunately the plot is somewhat tired, and the characters are rather flat and cliched, perhaps because the author hasn’t managed to successfully circumvent the memory issue she’s devised. The writing is clunky and the ending disappointing, so, sadly, loved the idea but not the execution.

How much can you remember? More than an hour, a day a month? Monos, the majority of the population can only remember a day, so they can't hold down any good jobs. What happens when someone is killed and the man investigated and the suspected murderer can't remember much? How can the truth be told? Unusual precise. A good thriller.

I found this book quite slow going at first and hard to get in too. I managed to stick with it and the story was quite different to the books I usually read but I quite enjoyed it in the end. It would be quite interesting to read some more by this author to see how they compare.

When requesting this book I must not have read the description properly as this book has a sci-fi element to it that is definitely not a genre I have an interest in. Please bear this in mind whilst reading this review.

This book is set in current times but in a world where there are two classes of people monos and duos. Monos can only remember one day but duos can remember two and are therefore more superior. Monos are looked down upon. Claire and Mark are in a rare mixed marriage, Claire being a mono and Mark a duo. Both monos and duos have to keep a diary and memorise information. Away from the world building, the body of Mark's mistress turns up. Mark is the number one suspect in her murder. The detective just has one day to solve the case.

I felt that there was a few holes in this world that the author had created and I was a bit confused as to how some things were remembered and other things had to be searched for in their diaries. It made no sense to me. The story is told from multiple points of view which I liked. I didn't particularly warm to any of the characters though, they were all annoying for different reasons. I could be wrong but I felt at certain parts of this story the author wanted us to feel some empathy towards Mark, I just wanted to slap him. This book was something a bit out of my comfort zone and I am pleased that I finished the book without struggling. I commend the author for that.

I only realised as I was reading this that the concept - a highly original society where monos can remember yesterday and duos can remember two days before - was familiar. Then I recalled a friday night live session at the Writer's Workshop Festival of Writing 2015 when I saw Yap read a section of her as then unpublished book. I was so glad to find that her novel had gone on to be published. Anyway this is definitely a different take. Part crime, part techo thriller, part sci fi. I really enjoyed it and its examination of what makes a memory and just how fallible memory can be. Highly recommend this fast paced engaging debut.

Thank you for providing me with the book

I read a few reviews before requesting this book and everybody mentioned that it is written in a different style and i was excited about it. I will probably be one of a few but i did not like the format at all. i found it a bit confusing.... present to past and in a few directions. I find with segments with different characters its hard on a kindle to go back to see which characters were doing what. I had a hard time getting into it. But it did have a good little twist towards the end that I did not see coming but that was not enough to make me like the book more.

A multiple character viewpoint novel told from the perspectives of the detective and the suspects. Very absorbing, and with several unexpected twists thrown in, my attention was firmly hooked 'till the last sentence.

A different take on.a detective book. How it would be in.a world where we can.only remember yesterday and nothing before that. An enjoyable and different read

The author has come up with an intriguing idea concerning memory which makes an interesting basis for her story. As the book progresses the story becomes rather far fetched.

This really deserved five stars! No, really, it did. But.....
Beautifully and fluently written, this debut novel will surely be followed by many more successful works. Until the teasingly delayed denouement I was more than happy to discount the weird (although strikingly effective) plot device regarding the two classes of memory within the population, but the final unravelling really served to detract from what, until that point, had been a cracking read. There was excellent use of the different perspectives of the key characters and a more than passable police procedural sub-plot. The various twists and turns of the plot were artistically revealed as the pace gathered towards the book's finale - so much so that the last 40% of the book (yes, that's a clue - read on a Kindle...) was read at breakneck speed to reach the end. However, for me - and I recognise this will be a personal judgement - the ending lacked the subtlety and craft of all that had preceded it. It really didn't need a plot twist that failed to do justice to the creativity of the bulk of the novel.

On a personal level, Yesterday isn't doing it for me - the author's style is clumsy and overblown, and I can't bring myself to care much about the central crime. I've read the first few chapters and don't plan to continue - but I do think it could be recommended to any reader who has a high tolerance for twisty thrillers and who would take a unique plot over a polished style.

An intriguing idea for a plot - what happens if everybody except you only had one or two days memory. Jumping from each character's diary and actual events needs getting used to at first. A brilliant read with lots of twists. Great first novel .

What a refreshing read.

Yesterday not only provides what is essentially an engrossing crime mystery, but wraps it up in an alternate reality where memory is either painstakingly committed as facts, or forgotten.

Did it work, well mostly I think. The premise whereby Mono and Duos live in a reality where there short term memory is completely wiped clean every 1-2 days seems a little too absurd once or twice, but the author does do an exceptionally job of making you accept what is simply the reality by suggesting that the alternative (our reality where memory is what we know it to be) is as equally absurd when viewed from the other perspective.

So yes, if the reader accepts it, the book has a lot to offer. Throw in a couple of twists and turns and in you are in for an enjoyable experience.

I must admit that I felt some of the interactions and narratives could have been portrayed slightly better. Yap said it best when she suggested that a conversation that reads well, is not necessarily how one would actually take place in real life (or something to that effect). Perhaps she strayed from that ideal once or twice. Additionally some of the investigative narratives seemed to be a little to 'Murder She Wrote'. But even with me harbouring these opinions, the book is still very enjoyable. And hey, perhaps these observations are simply normal for a world where the lack of memory plays such a crucial role. Perhaps only holding onto your immediate short term memory and crucial facts moulds the way we interact and act in general, to such an extent whereby what I lightly criticized is actually the intended behaviour.

Anyway, give it a go; I'm sure you won't be disappointed.

Thank you NetGalley and Headline for a review copy in exchange of an honest review

Favourite Quote: "Happiness is a process. Unhappiness is a state"

Yesterday is a high concept book that may well delight crime fans who have little exposure to speculative fiction - using a setting with limited short term memory as the framing device for a criminal investigation is bordering on genius. Sadly, the execution left me cold, with characters not just unlikeable (that's absolutely fine) but uninteresting, tending to extremes of self-pity or self-absorption. The narrative veered from tedious repetition (the core concepts weren't that hard to grasp, but were hammered home repeatedly) to overwrought histrionics, making it difficult to take seriously. However, it's a fast read, so I breezed through to completion; but I find it hard to recommend and wouldn't consider reading it again.

oh how much did I enjoy this book!! Brilliant premise of monos and duos, great storyline alongside. I raced to the end of the book, staying up late just to finish it. Beautifully written too, full of detail and description with no words wasted. I loved the detective, he could be the character in a series of books, but I suspect the writer will expand further than that. Fabulous twist at the end too. Recommended highly.

Wow! This book was so clever and unpredictable. I love stories like this. Real page-turner.

I really struggled with this book, I almost gave up more than once but I persevered until the end. It did have a bit of a twist but it wasn't enough for me.

Not a book I could get into at all. It's unusual for me not to be able to read an entire book, but, I couldn't get into this at all. Apologies.

Wow, this is a refreshing take on the crime detective thriller, adding in a dash of sci-fi to the proceedings. The premise of not being able to remember past two days max allows the author to make some timely comments on how this might affect the world we know today, and allows the plot to take turns that might otherwise have been too far reaching. I found it interesting and well paced, and would actually like to see a developing storyline for the future fearing the chief inspector in the story - I think that idea could tell a few more clever tales!