Thanks to NetGalley for providing me with a e-ARC in exchange for a review!

Long story short, this one wasn't for me. This book's setting is as bright and shiny as the cover, a world not entirely unlike ours except for the fact that there is very little land for people to live on so life centers around the water. I found the idea of this story being told through letters intriguing, but I found the plot aimless at times and I didn't seem to really know what was going on.

If you like light academia in a really cool setting, nerdy scholars solving a mystery and also falling in love, and some pretty flowery language, pick this one up.

DNF @ 15%

A Letter to the Luminous Deep is probably going to be polarizing. While I don't think I am necessarily the right reader for this (at least at the moment), I do think this will be an impactful read for others. My interest was piqued when I saw this compared to Emily Wilde's Encyclopedia of Faeries (plus cozy mystery? AND the cover?) but I just struggled with this. There is talented writing here with unique prose for sure but it unfortunately just went a bit over my head. It's all very formal and academic. This story is told through letters between 4 people, at different times. I had a lot of trouble distinguishing the separate voices of the letters and this wasn't helped by trying to also pick up on the world-building. The world has almost a whimsical steampunk-y vibe that reminds me VERY subtly of A Series of Unfortunate Events. From what I did read, there is a specific type of humor that as a "quirky" millennial who entered college at the boom of the Hipster era that I did find charming (I'm not sure that is the right word, iykyk) especially from E. I might try to pick this up again in the future for more of E as I do think there might be some reliability there in terms of struggles.

If you are interested in this, I HIGHLY recommend reading the sampler first! (please read the sampler) I know the right audience is going to really enjoy this!

Note: I won't be leaving a star rating attached to my review on GR because I don't usually for DNFs.

Big thanks to Orbit and NetGalley for the opportunity to this eARC!

I dove into Sylvie Cathrall’s debut novel, A Letter to the Luminous Deep. The story unfolds via letters between E. and Henerey, two souls who find solace in words.The underwater setting? Mesmerizing. I haven’t read a book quite like it - but the format did remind me of the Emily Wilde series. However the plot didn’t quite hook me. The book was a little slow for my taste but I’m eager to see what Sylvie writes next! I’m grateful to NetGalley for the early peek.

Rating: ★★★☆☆
Disclosure: I got this ARC in exchange for an honest review.

This was such a fun and unique book! The whole story unfolded through correspondence between two characters in real time and recovered correspondence as they helped piece together the mysterious disappearance/death of their siblings.

There were aspects of clean romance, found family, LGBTQ+ representation, sci-fi, and fantasy. This book has a little something for everyone!

Thank you to NetGalley and Orbit for providing me with an ARC of this book. This review was left voluntarily.

I was really excited about an academia based fantasy novel. I really enjoyed the academia aspect and liked the idea of the book. I think the writing style with the letters was personally not for me but I know many people who love it. It’s a slower build up but it was a cosy read.

Thank you to Orbit Books and NetGalley for providing me with an eARC of this book!

I was so hopeful about this book- it sounded so intriguing and that cover is just absolutely gorgeous. But I just could not force myself to finish it. I read 33% of this book and I still could not tell you any more of the plot than two people exchange letters documenting their siblings' final months (days? years? i simply could not tell you). When I say that this book moves slow, I mean it is glacial. Which may work for some people. But it just did Not work for me, particularly because I was having an extremely hard time getting into the story and understanding the setting and world in which this was all taking place. It seems like this is maybe a world that is largely underwater, but if that's the case then why was Sophy and E's house being underwater so fascinating to literally every other character in the book? What other options are there but to build underwater if that's how the majority of the world is? Is literally everyone else in this world living on boats? How would that even work, particularly for establishing campuses for certain groups of study, as is established in the book? I just don't understand, and I couldn't visualize most of the technology or creatures the characters talked about in their letters. This book would have been greatly improved with the addition of sketches like the ones referenced by the characters literally every other page. I think that would have helped me get a better sense of what was actually happening and what they were discussing.

I imagine that writing an epistolary novel is incredibly difficult and daunting; of all the really successful ones I've read (not that I've read many), one of the biggest driving forces that make them so enjoyable are the characters and the voices of the characters captured in their letters. I think this book really falls short in that regard; there are 4 different main characters all writing letters, but if you flipped to any random page or letter and asked me who was writing it, I wouldn't be able to tell you. All the characters write the same and sound the same; it's incredibly monotonous and repetitive. I really, really wanted to like this book and I tried very hard to push through, but unfortunately I think the writing style and the world just aren't for me.

This was phenomena! Cathrall's writing is enthralling and evocative; I felt transported into their world in a way few books have managed. I will be counting the days to read more of this story in her next installment.

I thought this novel was very innovative in concept. The undersea culture and setting were lovely, the epistolary format worked nicely, and I felt the book was very cozy--a good spring read, if you will. What I felt this book missed was relatability. The characters didn't truly jump off the page for me. I felt that while the setting and writing were both 5-stars, the neutrality of the characters (barring, of course, the exuberant and quirky late professor) made the book fall flat for me. I never felt won over to one or more character's causes, didn't feel curious about the mystery aspect of the book, and after the slow ascent to the middle of the plot, I found that I was just running on vibes with no real excitement toward the next big plot development. First, I must acknowledge that mystery is not my favorite genre, and this novel led with mystery far more than I had anticipated. While I do believe this book will succeed on the market largely due to the novel core concept (undersea), it wasn't my favorite.

I finished the final chapter of this book and sat in silence for several minutes. I thought to myself, "what did I just read?" Is it a historical romance with a strong Jane Austen vibe? Yes. Is it a portal fantasy brimming with brave explorers and ancient lore? Yes. Is it a steampunk sci-fi novel set underwater? Yes. How this author managed to create a cohesive blend of all these elements is beyond me but it absolutely works and the story feels perfectly balanced across all of them.

The plot takes place on a world completely covered in water save for a single, small landmass. Mystified by the circumstances that led to the demise of their ancestors, the inhabitants of this world have created an academic society that spans three campuses, each with it's own unique ecosystem and collection of scholars. We're quickly introduced to E. Cidnosin and Henerey Clel a curious pair of pen pals that have presumably perished in a recent accident. Through their letters, and those of their respective siblings, family, and friends, we learn more about the blossoming friendship between E. and Henerey. What begins for their siblings as a glimpse into the last days of lost loved ones becomes a mystery in need of unraveling that gathers momentum with every page.

What I thought would be an Achille's heel - storytelling through letters - turned out to be the book's biggest triumph. The sequence of these letters was masterful, strategically revealing more of the story in a consistent and yet unpredictable way. I felt less like a reader and more like a voyeur to the private thoughts and feelings of these characters.

This book was (for lack of a better word) a luminous read and I loved it so, so much.

How do I begin to summarize how much I love this novel?

Firstly, I am a sucker for an underwater setting. Books set in the ocean can either be serene and calming or dark and unsettling and I feel like this book managed to do both beautifully. The world building of the Deep House and the various campuses, exploration sights, and the mysterious island were so well done that it felt like I could see them.

Secondly, I love storytelling through the epistolary format. Each character felt like they had their own distinct voice and personality, and I came to love every single one of them. Cathrall explored so many different relationships from familial to romantic, and these added even more depth to the world building as we saw the world through the eyes of the characters. I could not say whose relationship I enjoyed more, but I will say watching E. and Henerey’s romance swell had me kicking my feet.

Lastly, I love the mystery, and the build-up to the mystery. It pained me to put this book down and go about my day, as if I wasn’t going to be thinking about it the whole time! Cathrall so wonderfully weaves little details that come together in a rewarding manner towards the end. The only sadness this book gave me was that I will have to wait for the next installment to find out what happens! And even that is not too bad, because it means I will be able to sink back into this world with these characters.

Thank you so much to NetGalley and Orbit Books for my eARC of “A Letter to the Luminous Deep”! All thoughts are my own.

The premise of this book sounds so good, and I wanted to love it, but I ended up just liking it. I think the idea of an epistolary story appealed to me, but I really didn’t enjoy reading it that much. I did get sucked into the mystery a bit, but I tired of reading letters and emails.

OMgeee!!! That was the most PERFECT cozy fantasy composed of mixed media correspondance. I am normally not a lover of book in this format, but this one STOLE my heart. I was absolutely in love with the characters, and about 40% of the way in I was ready to pack my bags and join them. It was the mystery aspect of what happned to these two charming characters that had me hooked though, as I was so attached from the first letter that I needed to solve this mystery as much as their siblings did.
Another thing that was so unique was the setting, a fantastical world that basically lives on the water.
This world used to be a floating island in the sky, and something happened years before this novel takes place, but the sky civilization came crashing down, and now there are 3 different areas each with its own unique standards of living. Magical, vivid, intriguing but also a little scary !!
This is definitely my go to recommendation for fans of low stakes, cozy fantasy readers who like a subplot of romance. And won my heart as the best slump fixer ever, as I read this in-between to heavy fantasies and it helped me stay in the fantasy state of mind without using so much brain power. I will definitely be reading this again. Thank you so much to the editor for the copy and to Slyvie for signing my copy, and most importantly to my amazing "boss"/friend Tory for getting me a signed ARC!!!

I wanted to desperately to love this book however, after a chapter, I just knew it was not a fit for me. after looking through the rest of the book, my suspicion was confirmed. This book is 100% composed of letters back-and-forth between characters as a reader than just several letters. I could not even bother to go forward because that writing style alone does not work for me. This book was officially DNF’d but I hope it works for other readers out there.

I enjoyed the majority of this book. The epistolary format and the cozy mystery/romance made me flip pages. Once we got to the fantasy boom at the end, the story lost me. I felt it was too much at once. I did enjoy the story enough to keep the second book in the series on my radar. The best part of the book was the stunning cover. 3.5 stars rounded up!

Thank you Netgalley & Orbit for the opportunity to read this eARC!

Overall, I love the cover and the story is a unique concept. The format of letters telling the whole story was interesting, however because of how formal all of the letters seemed, it took me a while to get through and made the book seem even slower. I enjoyed the characters and the world building!

Dear Author,

This could have been a prologue.

Sincerely,
A disappointed reader

P.S. Letting your audience know whether a book will be a standalone or part of a series can affect the reader's enjoyment!


I was raised on a steady diet of Cheerios and The Little Mermaid. I adore any underwater fantasy I can get my hands on. Going into this one, I thought it would be an automatic new favorite. An epistolary novel filled with romance and deep sea exploration? What else could I need in this short stint called life?

A plot. That's what else I would need.

Before raining on this book's water-filled parade, I enjoyed certain aspects.

Building complex characters with only letters is difficult, but the author did a beautiful job! There are two sets of letters: E's and Henry's, and their siblings (respectively), Sophy and Vyerin. All four personalities were built without the correspondence reading: "So-and-so has this specific character trait and this personality type!" I won't delve too much into the letters to avoid spoilers, but know the characters were easy to cherish and adore.

E and Henry's romance made me swoon. The quintessential "talk nerdy to me" couple. Because of how their relationship is built, it is the most authentic love story I've read in ages. Watching E and Henry building a bond of mutual interests into something more was pure and wholesome. E and Henry both feel out of place within their communities. (I was not expecting such excellent OCD and anxiety rep!) Because of their differences, their relationship starts awkward and purely academic, even as they both yearn for more meaningful connections. I could write a thesis on why E and Henry's romance is for the history books, but I digress.

Despite the unique writing styles and lovely characters, not a single thing of importance happens. I am a character-development-over-plot reader, but something has to happen to hold my attention. I read this thinking it was a standalone. I don't know if this is set to be a duology or trilogy, but there has to be at least one more book since none of the action happened til the last 5%. If the book had some aspects of action, it would have been easier to get through, but the author was focused only on introducing a small cast of characters and building the setting. Yeah, the world was neat, but not enough substance to justify a full novel.

Despite my gripes, I will be continuing with the series. This is a debut work, and I already see the immense potential the author has. As long as you go in with the mindset that you'll have to hold out til the sequel for action, you won't be disappointed like me. There truly is a lot to love. Slow and steady wins the race.

Thank you NetGalley and Orbit Books for the advanced copy in exchange for an honest review. All thoughts and opinions expressed are my own.

I have such differing thoughts about this book - it’s hard to know if I enjoyed it or hate read it? On a positive note, the characters were endearing and the relationships (familial and romantic alike) were conveyed with such sincerity you can’t help but smile! The academic focus and underwater setting were very unique. I think the best way to consume this story would be to read a chapter a day. The story is intriguing enough but certainly not gripping and extremely slow in pacing. The focus is definitely more on the vibes (& on more than one occasion, the vibes put me right to sleep). Regardless, the mystery aspect to this story left on a good cliffhanger and I think there will actually be more plot in book two? I’m invested enough that I will continue on in the series but will definitely take it at a slower pace. I applaud the author for the ambiance of the book and conveying such emotions and story through letters alone. Lastly, hopefully this does not come across as a negative review. Truly it’s meant to be informative for future readers and what I wish I would have known prior to diving into this story!

I loved this book so much! I cannot wait to continue to read about this journey. I’m in love and rooting for every character. This is my favorite read of 2024!

A Letter to the Luminous Deep tells the tale of E. and Henerey's relationship and eventual disappearance told through their collection of letters to one another. E. lives alone in her family home called the Deep House, built in an underwater reef. When she witnesses an unknown creature swimming outside her home, she writes to scholar Henerey Clel to help identify the mysterious creature. They quickly develop a mutual affection for one another through their correspondence and work together to uncover even more mysteries E. stumbles upon at the Deep House. A year after they disappear, E.'s sister Sophy reaches out to Henerey's brother Vyerin to find out exactly what happened to their siblings by piecing together E. and Henerey's letters to one another as well as any relevant personal correspondences Sophy and Vyerin had leading up to the disappearance.

The cover alone got me interested in reading this book. The unique combination of a magical world in the depths of the ocean with an academic romance had me hooked. The writings between E. and Henerey are heartwarming and elegantly build the mystical underwater world they inhabit. The letters between the two are my favorite part of the novel. I did struggle with understanding the logistics and history of their world, but I was able to comprehend the elements that are most important to the story.

Considering I don't often read epistolary novels, it took me some time to adjust to the format of the novel. Once I got a grasp on the connection between the characters and the intentions behind their letters, I was able to immerse myself in their lives and experience their relationships unfold. Cathrall's decision to unravel their story through the academic correspondences turned love letters between E. and Henerey creates a compelling story and charms the reader to the two instantly. However, the Sophy and Vyerin plotline is not as strong when told in the same epistolary style. Perhaps their side of the story could be more fleshed out in prose, since some of their notes (especially near the end of the book) seemed to be awkwardly included with odd justifications to maintain the epistolary nature of the novel.

I'm rating this book a 3.5/5 because I did enjoy the relationships, mystery, and world established in the book. I believe there are a few aspects that could be improved, but it is definitely a unique book worthy of praise. I did not know going into this book that it would be the first in a series, so I was left a little disappointed that as the end neared, I was provided with more questions than answers. I hope the sequel comes soon so I can find out how the story continues!

Thank you to NetGalley and Orbit Books for the arc.

A Letter to the Luminous Deep is a beautiful exploration of the bonds between siblings and lovers. Its mysterious, intriguing, and almost ethereal.

It took me some time to get used to the epistolary format, but once I understood the language and got used to the writing style, this story was such a joy to read. I loved all of the relationships and teaching them evolve through their various correspondences. I appreciated the mental health representation and how E.’s curiosity and trust allowed her to become more open and sure of herself.

I thought this was a standalone novel so was not expecting the cliffhanger. I cannot wait to get my hands on the next novel to see how everything plays out!

Thank you to Netgalley and Orbit Books for the e-arc in exchange for an honest review.