This book is absolutely gorgeous and I would recommend it to anyone who loves reading. It's produced by JJ Abrams who came up with the idea of having a book within a book, characters interacting through margin notes and from old school textbooks which had students writing in the margins. It's written by Doug Dorst who was hired by Abrams to write it.
They say this novel is their love letter to the written word and, oh boy, it sure is. Once you open the case slip you'll find what looks to be an old library book (with a library sticker and ‘borrowed’ stamp!), the pages feel amazing, it's printed in full colour (must have cost a fortune!), smells gorgeous (like old books), has multi-coloured notes in the margins and there are lots of pull outs (such as maps, letters, napkins etc) throughout the book.
First of all, I haven't actually finished this book yet and it's the kind of book that I don't think you can ever be finished with. It has many layers to it and you're constantly learning something new. I don't think there's any certain way to read it or conclusions you must draw but it took me a while to figure out how to approach it.
Basically there's the main storyline The Ship of Theseus written by the mysterious VM Straka and his editor. And then there are Jen, an undergrad student who finds the book and begins to write in it, and Eric, a begrudged postgrad student of whom the book kind-of belongs to (aka he stole it). They communicate via notes in the book as they try to learn more about it, Straka and themselves.
Some people recommend you read the full Ship of Theseus book first without the notes but I find it quite heavy and lacking without the notes whilst others just try to read every single page with all the notes. I chose a middle ground after a lot of research and read each chapter of Theseus then went back to read the first sets of notes by Jen and Eric before continuing. There are many sets of notes written at different times and read-throughs which can be confusing and spoilerific. Luckily they're colour-coded so you know what time-frame they're from and I'd go back to read through the later notes after reading through the whole book.
It reminds me a bit of A House of Leaves by Mark Z. Danielewski as it uses space and words themselves as a storytelling device but it's not as dark or convoluted. Equally as confusing though. I don't think it's a gimmick as some people do and love the ideas behind it. It's very clever and unique. It's a serious sit-down afternoon book with tea for me and I'm enjoying indulging in it slowly.