This book is so wonderfully charming. It has everything going for it. A mystery, a house beneath the water, epistolary letters from friends and love interests! It literally has everything you need in a book. I was blown away by Cathrall's use of characters and scene setting, and the amazing showing of representation. All of it was 10/10 and one of the best experiences.

If you like epistolary novels and fantasy books, you'll find much to love in A Letter To The Luminous Deep. I’ll admit that I mostly gravitated toward this one at first because of the cover. How could you not look at this book and immediately want it in your hands? And then come to find out its an epistolary romance with a dash of academia and an underwater world? Its a very specific kind of catnip for me and on the top of my books to read this month pile.

Unfortunately, I tried many times to continue reading but the writing style and letter format was not for me. I pushed myself but fi ally dnf at 10% . I do believe this could be a great read for someone however i could not get into to it. Thank you Netgalley and Orbit for the gifted eARC. All opinions and thoughts are my own.

I loved how this book was written. It was light hearted, cozy, easy to read and very unique. I have never read a book that was told through letters so I found that to be very intriguing. This book did not disappoint! I loved it and I definitely recommend it if you are looking for a gentle epistolary book

This book was very unique and yet had a lot of familiar themes that I really enjoyed. I was pleasantly surprised and really enjoyed this story.

This was narrated completely with letters and journal entries and book excerpts, the talent is just >>>>

I was absolutely gripped by the plot - Henery and E. (two of the MCs) who were penpals to lovers disappeared in a mysterious seaquake. Now, a year later, their siblings Sophy and Vyerin piece together Henery and E.'s letters to each other as well as their letters to them and other acquaintances, and attempt to solve what happened..

The book is mostly set in futuristic underwater homes and expeditions, and that made the story even better! It was so cool! Also, Henerey and E.'s romance was so swoony and wholesome 😭

It ended on a cliffhanger!!!!! I need book two so badly 😭💔💔

-- ty to the author, the publisher and Netgalley for an advanced copy!

This epistolary novel is a bit dense (the two main characters are very scientific) at first, but the mystery of their disappearance spurs you on. It was still hard to get through at times, but then the fantastical aquatic world pulls you back in.

So, I wanted to love this. I really did. I even waited until I was done reading another series so I could focus on this book. But it just didn’t do it for me.

I don’t know if it was the letters back and forth that really didn’t draw me in, I felt like I was constantly pulled from the story. If this was done differently, if the story was done without the letters, I think I’d enjoy it so much more.

I liked aspects of this.
I liked the characters and I liked the premise. I love anything taking place in the sea. I just wish it was done a bit differently.

I always forget how much I love epistolary books! I loved the world building here, and each character was so charmingly unique.

This book, told through letters, journal entries, and reports, offers an amusing writing style that may have made me chuckle once or twice, but that wasn't enough to save it. WHYYYY couldn't this have held true throughout the entire book??? Instead, every character’s voice felt indistinguishable from the next, making it difficult to connect with them. I don't think I remember their names now. Jeeez. While the story’s premise is intriguing, the lack of unique voices and the slow pacing made it hard to stay engaged, and I often had to force myself to continue reading (often having to reread sections).. OH. and the book ends on a cliffhanger, which I wasn’t expecting. Totally thought this was going to be a standalone. I did enjoy parts of the book, but ultimately, it didn’t live up to its potential. The cover is lovely though.

I ended up DNFing this book. While I was extremely excited about the overall premise, I was so co fused from the start, and there was nothing that helped that. While sometimes readers are dropped into the middle of stories and have to discover the context as they read, the epistilary nature of this book did not lend itself to any kind of clarity for the reader. I got 30% through and could not tell you a single thing about what was happening or what it meant. I also did not enjoy the writing style and felt the overall editing left much to be desired.
I do not fail to finish books often and was very disappointed to find this was the case for me with this novel.

⭐️: 4.5/5
🌶️:🚪 None :)
Format: 📱

This was stunning. Literally STUNNING. The list of things I loved is long:
EPISTOLARY STYLE: This entire thing is written in correspondence between characters, and it is EVERYTHING. It's such a unique way to get to know the characters, and it hooked me like, RIGHT away.
INCOMPLETE WORLDBUILDING: Okay. what I mean by this is that there aren't any info-dumps. We simply learn the world as things are mentioned. You build the world by picking up on bits and pieces throughout, and it allowed me to immerse myself in the plot and have things built around me. I really loved that. I was able to get invested in the story and characters so much faster.
SUBTLE ROMANCE: Ummmmm This was SO CUTE. The romance was so subtle, and more of like, a classic romance. The romantic little notes between Henerey and E. are somehow MORE romantic and thrilling than a spicy smut novel. This is a book Anne Shirley Cuthbert would have loved, and I feel like there's no higher praise??

I cannot wait until book two. CANNOT WAIT.

Sitting mercifully renewed on my NetGalley shelf for the bulk of 2024, I’m so grateful I had the opportunity to return to this unique and soulful mystery expertly unraveled through a series of “correspondence” between Vyerin Clel and Sophy Codnorghe regarding the disappearance of their siblings Erudition “E.” and Henerey.

The book opens with a sweet letter from E. to Henerey regarding her observation of an unknown species of eel she observed from the porthole of her home—the famed “Deep House” and it is not long before we realize that this was the start of a correspondence relationship (and a tenderly developed romance) between two anxious individuals ill-fated to a mysterious and explosion and disappearance. The book continues through the correspondence of their siblings forming a friendship through their journey to share their own archives and the timeline leading to the fated ending.

This light academia book is not for everyone. If you are seeking fast-paced, immediate gratification, high stakes story telling, this book may try your patience. But to me, there is great reward in letting the author do what she is clearly skilled at: allowing the story to blossom at a delicate pace.

Often my complaint about books lately is how immediate the plot unravels or romance spikes, so for me, this novel was was a piece of art, empathy, and ultimately a love-letter to great story-telling.

Fabulous! Love the unorthodox setup! It's so imaginative and fun! Teh author makes you invested in all the characters and you want to know what happens to them-the missing ones and the ones left behind.
Can't wait for the next one!

This was one of the most well-written books I've ever read. Every sentence made me want to pause and just absorb it. It was a bittersweet tale that still conveyed hope and longing. Well done!

I personally cannot believe how long it took me to post one of my favorite reads of 2024. I read it while recovering from surgery and life was completely impossible for a while after that. But I refuse to forget about Sylvie Cathrall's “A Letter to the Luminous Deep.” I read an ARC provided by Orbit Books but once released I immediately went to purchase my own physical copy which I treasure <3 I will certainly be purchasing and reading book 2, “A Letter From the Lonesome Shore,” coming May 2026 (which…I really *cannot* wait for).

Nearly every layer of this story is unique in some way. Between the epistolary narrative style, dual timelines, and the innovative scholarship-focused world crafted by Cathrall, I don’t think I have read anything quite like “A Letter to the Luminous Deep.” However, if you are a fan of The Adventure Zone’s Ethersea campaign, you might enjoy the atmosphere and vibe of the world in this novel as well.

It is hard to explain what this book means to me. As an academic, I loved exploring the ideas around what a world built by scholars might look like—both the advantages and downsides. Some of the issues explored definitely hit hard (especially as I am now choosing to leave my doctoral program…sigh, these characters would completely get it). Additionally, while I do not have OCD, E.’s day-to-day struggles and triumphs with mental illness felt so relatable and representative of my own struggles with mental and physical illness. Her budding friendship with Henerey is so sweet and ugh, the way their relationship brings together their grieving family members in the wake of their disappearance is beautiful. Again, I cannot believe I took more than half a year to review/post post about this. But it is no reflection of the book itself. May 2026 cannot come fast enough!

Thank you to Netgalley and the Publishing Company for this Advanced Readers Copy of A Letter to the Luminous Deep by Sylvie Cathrall!

2.5*

I've waited a long time to add my review for this DNF at 30%, because I know this book will work for some people. It just did not maintain my interest and the writing style was not my favorite. The plot and pacing are very slow moving and the writing style and vocabulary choice make the letters from the different characters sound almost the same. I think each character having a distinct voice is very important, and this just didn't have that. I liked the characters and their mental health representation, but everything else left me very underwhelmed.

Thank you to NetGalley and Orbit for providing this eARC! All opinions are my own.

Review: 3.5 star

I was fascinated by this one due to the beautiful cover and the idea of the story being told in a letter exchange format with romance thrown in. A big bonus also occurs in a sea/ocean fantasy and academic setting.

It’s told in multiple POVs with the exchange of letters starting with Sophy (E’s sister) and Vyren (Henry’s brother) whereby they were trying to piece together what happened to their siblings’, E and Henry’s mysterious death in the form of their siblings past correspondence and journal entries. This also adds a mystery element to it.

I do so love the idea of it being told in letters, journals and occasional instant message formatting - it can be such a fun and unique way to tell the story. Unfortunately, this was a little overwhelming for me since the writing was done in Regency England style, and I get overly bored with that kind of writing. To be fair, each character had a distinct writing style, but Sophy and Vyren’s correspondence was always followed by a past letter from Henry or E, leading to a random shuffle between present and past and some confusing moments!

As much as I love world-building, this story moved at a snail's pace, and nothing important happened until the last 20 percent of the book. *welp*. While I did enjoy the slow-burn romance between Henry and E with the nerdy moments, I would not say this is a romantic book but a fantasy book with a small romance subplot.

Overall, I enjoyed the book and am interested in reading the next one. Note that this book is part of a duology, with the next one coming out in May 2025.

Thank you, Hachette Canada, for providing me with this e-arc.

First of all, the cover is absolutely gorgeous. The book itself sounded interesting, which is why I requested an ARC on NetGalley.

But unfortunately, the cover was the only good thing.

This book was painfully boring. I made it to around 20%. I tried to flip forward to see if the writing style would capture my interest, but it didn’t. I do not see at all how this is classified as fantasy…

Besides the story being overall boring, the writing style felt overly technical and dry. It often felt like I was reading an academic paper rather than a novel. There were too many asides and references that seemed important within the universe, but they only served to interrupt the flow of the narrative. The descriptions felt like reading a textbook, making it hard to stay engaged. This book just wasn’t for me.