"A charming fantasy set in an underwater world with magical academia and a heartwarming penpal romance, perfect for fans of A Marvellous Light, Emily Wilde's Encylopaedia of Faeries and The House in the Cerulean Sea.

A beautiful discovery outside the window of her underwater home prompts the reclusive E. to begin a correspondence with renowned scholar Henerey Clel. The letters they share are filled with passion, at first for their mutual interests, and then, inevitably, for each other.

Together, they uncover a mystery from the unknown depths, destined to transform the underwater world they both equally fear and love. But by no mere coincidence, a seaquake destroys E.'s home, and she and Henerey vanish.

A year later, E.'s sister Sophy, and Henerey's brother Vyerin, are left to solve the mystery, piecing together the letters, sketches and field notes left behind - and learn what their siblings' disappearance might mean for life as they know it.

Inspired, immersive, and full of heart, this charming epistolary tale is an adventure into the depths of a magical sea and the limits of the imagination from a marvelous debut voice."

I mean, I can't be the only one who's dreamed of living under the sea?

Unfortunately, I had to DNF this book 30% through. It was my first epistolary book, and I had a really hard time grasping what was trying to be conveyed. I was confused from the beginning, and was having a hard time following along. I tried to push through, but I had a really hard time finding the motivation to pick up the book again and continue reading.

Don't get me wrong, the writing itself was extremely poetic, but maybe epistolaries are just not for me.

Thank you to NetGally for the opportunity to read an ARC of this book in exchange for an honest review.

I enjoyed this book FAR more than I thought I would. Where I've seen negative reviews is actually what I liked most about it. The book is told entirely in letter form. I assumed it would switch after the beginning but it did not! I also rarely read (or enjoy) mystery type books. Because it's told through letters, you're finding out the information in the same time as the main characters are. This made it to be quite suspenseful and I couldn't wait to get to the end. I LOVED all of the main characters. E is lovely. Sophy reminded me of my caretaking sister. Henerey was likable and lovable. Vyerin was level-headed and respectable. I genuinely cared about all the characters. If I was able to read it faster it probably would be a 5 star book. It leaves off on an extreme cliffhanger and I absolutely can't wait for book 2!!

Side note: OCD was very well represented in the story.

Highly recommend to anyone who enjoys mysteries and the idea of romantic letters to pen pals. I'd also put it in the sci-fi category. Highly recommend. Thank you NetGalley, orbit books, and Sylvie Cathrall for the eARC.

While I used to think I didn’t enjoy epistolary-style stories, I’ve read a number of really great ones over the last few years to the point where I’m now wondering if I had originally just read a few not so great ones and judged the entire format just on that. As it stands, the “Emily Wilde” series has done a lot to reform my opinion, and this one sounded very similar, not only using a similar format but also leaning heavily into the academia side of fantasy and science fiction. Let’s dive in (heh, how clever)!

I think this will be one of those books that might be a struggle for the average fantasy reader, but will also garner devoted fans who also adore it! This largely comes down to the overall style and tone of the writing. Like I said, “Emily Wilde” is definitely a comparable title, but in comparison to this one, that is “epistolary academia fantasy lite!” Pretty much take the tone and style of that book and magnify it and you will get this story! There’s simply more of everything: more focus on the intricacies, oddities, and cultures of academia, more complicated and verbose sentence structure and specialized vocabulary, and even more commitment to the epistolary style. In “Emily Wilde,” many times her journal entries would read as a straight narrative. Here, the author is fully invested in telling a story only through letters and supporting documents, so the narrative plays out in a more distanced way.

And I loved all of this! I love authors who can so naturally capture this sort of long-form, “old fashion” style of writing where sentences are long and word choices are elaborate. I also really enjoyed the slow reveals of the many mysteries and secrets at the heart of the story. Not only do we have the remove of learning this story through the more limited form of what letter writers choose to share with one another, but we also are piecing together what happened in the past as the siblings of another pair of characters work to compile the correspondence of two characters who have passed away.

I really enjoyed all the characters we have here, both pairs of writers feeling fully realized and interesting. E, I think, rose to the top simply for how well the author managed to portray a character who lives with high levels of anxiety that affect how she lives her life. In the past, I’ve often found myself frustrated and disappointed by the rather surface level portrayal of characters like these, but the topic is so perfectly explore in E, both honestly depicting her struggles, but also not defining her by this trait. I also really enjoyed Sophy, her younger sister who has her own adventure and must later work through E’s past letters to try to discover what happened to her. Sophy is a much more action-oriented character, and the contrast between them was nice, as well as the loving, strong sisterly relationship we see between them.

I’ll also make a small plug here with regards to the genre of this book. I’ve seen a lot of reviewers calling this fantasy, but I think this is a perfect example of a science fiction novel that doesn’t take place in space. Too often, it feels like readers and marketers think that “science fiction” and “space” are synonymous, but this book perfectly highlights why science fiction needs to be remembered as being a broader category. In almost every way, this book much more closely aligns with the conventions of science fiction over fantasy, especially with its academic focus, which is very scientific in nature. Not only that, but the history of this world and the mysteries we discover all fall in better line with science fiction than fantasy (in many ways, it reminds of the movie “The Abyss.”) This isn’t necessarily a hugely important distinction, but I do think science fiction readers might miss this one due to the fact that it’s being called a fantasy story much of the time. Anyways, there’s my TED talk on that topic!

Overall, I really enjoyed this book! I was surprised to find that it’s the start of the series, and it does end on a mild cliffhanger. But there were so many interesting twists and turns (both with the larger mystery and with a few character turns that really took me by surprise) that I can’t wait to see where things go from here! Readers who enjoy rather long-winded, heavily academic fiction will likely enjoy this one! Also those looking for a lovely slow-burn romance!

Rating 9: Cathrall embraces the full beauty of the epistolary novel, creating a vivid, immersive world and peopling it with characters I’d follow into the darkest depths!

(Link will go live on The Library Ladies on April 26)

Showstopping. Amazing. Breath-taking. I hope you brought a plate because this book ATE. Where do I begin to explain my love for this book? This is an epistolary fantasy tracing the journey of Sophy and Vyerin after the sudden disappearance of their siblings, E. and Henerey. Following their letters and messages, we can see these characters develop a deeper relationship and uncover the mystery of their lost siblings.

Although confined to the epistolary format, Sylvie Cathrall was able to weave an intricate and whimsical underwater world that had me wishing that I lived underwater. The world-building is nothing short of captivating, with a unique academia system adding depth and richness to the narrative. Cathrall's vivid descriptions paint a vibrant seascape that is both immersive and delightful.

The characters are the true jewels of this tale. Witnessing E. and Henerey's romance unfurl was a joyous experience, made even more delightful by sharing the same timeline as Sophy and Vyerin, who eagerly observe their siblings' love story. Yes, I must confess, I felt like a nosy family member, but the narrative had me fully invested. Moreover, the supporting cast shines just as brightly, with each character bringing a distinct flavor to the story.

As someone who understands the struggles of OCD, I found solace in the portrayal of the author and E.'s shared experience. It was refreshing to see OCD depicted not as a defining trait but as one facet of their complex personalities, adding depth and authenticity to their characters.

If you are looking for a fantasy that will warm your heart and you can get lost in, please read this one. I need more people to talk about this book.

Thank you to NetGalley and Orbit Books for allowing me access to the e-Arc.

3.75 stars

I loved the concept of this book. It gave me the same cozy fantasy with a mystery vibe like Emily Wilde’s Encyclopedia of Faeries and The Memoirs of Lady Trent but make it under the ocean.

This book follows the reclusive E. and a scholar Henerey Clel who connect through writing letters about their interests. They both seem to deal with social anxiety. I love their conversations. I thought it was interesting that we are given different points of view of letters written. Years later, we get new views from E.’s sister Sophy, and Henerey’s brother Vyerin. They are trying to figure out what happens to their siblings. I did think at times that it was a bit overwhelming. There were so many conversations going on at once.

I would still recommend this to anyone who likes these kinds of books!

This was my first epistolary fantasy and I might have just found a new genre to read! It was thrilling to read this story from the POVs while watching relationships grow and bloom!!

I will say it took a little bit for me to fully get into it, but once it picked up… I was hooked.

All of the characters are much fun to follow. As I said, it was great to meet these characters right as they were meeting each other. We get to see friendships bloom, romantic relationships blossom, and sibling dynamics play out in full effect. This is NOT a book to miss out on.

I will absolutely be reading the second installment in this series as soon as it releases (if not even sooner.. I hope I get the ARC for it!).

Very thankful that I was granted this ARC!!

Thank you to Orbit Books and NetGalley for sending me an ARC of this book! I hate to do this this, but I really struggled with this story. It sounded magical and wholesome but I found the delivery to be underwhelming. I had a hard time following the letters between the characters and I had to reread pages because I wasn't fully engaged. I may revisit this again in the future, but for now, it wasn't for me.

Thank you to Netgalley and the publisher for providing me with an ARC of A Letter to the Luminous Deep! I’m a sucker for the epistolary genre, and this novel was right up my alley. I also really enjoyed the archival aspect of the story and how the written content expanded beyond the letters themselves. While I enjoyed reading the correspondence between different characters, however, I did feel that they were not differentiated enough. All of the letters read the same in terms of tone and structure, and I felt that they could have used more in the way of personalization. Additionally, in terms of the characters themselves, I wish there had been a greater emphasis on developing the relationship between Henerey and E. Despite a slower pace in the beginning and middle of the novel, I didn’t feel as invested in their romance as I had hoped and their relationship seemed a bit too rushed in general. Aside from these qualms, I enjoyed the world-building and prose of the novel—it was easy to imagine and held a lot of intrigue for me. I was unaware that this novel was the first in series but I am curious to see how the story continues to evolve. Overall, despite some issues, I enjoyed this read and plan to pick up the next installation in the series!

Thank you to NetGalley and Orbit for this ARC of A Letter to the Luminous Deep in exchange for an honest review! What a really fascinating and unique story! This is one of only a handful of epistolary novels that I have read, but it's a style of story telling that I always enjoy! This is a pretty cozy fantasy I'd say and there is such a beautiful underwater setting that I really found to be so incredibly done! Sylvie Cathrall has a gift for bringing a world to life, that's for sure. The most creative and enjoyable aspect of this book for me was absolutely this atmospheric world it takes place in! Definitely glad I read this book just to experience that!

The whole concept of this book really appealed to me as I said. I think telling a story through letters can allow for some heartwarming moments of connection between characters that other stories might not be able to achieve. A Letter to the Luminous Deep does a good job with that! I really loved seeing relationships growing through the letters as the story and the mystery unfolded!

This book is one hundred percent letters and other pieces of writing. That is not going to work for everyone. Some people are going to want things they usually find in books, such as dialogue not just recounted in letters. I think if you're giving this book a try, you should know you're getting a unique story in several ways and the format is one of them.

I think the language is at times very academic (or at least pretty formal). Some people are going to find this slows down the story. This was not a quick read for me, and it took me some time to really get into it. That being said, I didn't mind taking my time with it because that felt very natural for a cozy underwater tale. However, I expect others won't be as engaged. It's just going to be a matter of opinion at that point. I think this is a book you have to be prepared to keep going even if you feel like there is a lull in the story. The last third or so definitely picks up. There is absolutely more to come in a second book, as is obvious from the way it ended. And I'm looking forward to that next book!

So, this book is not going to be for everyone at all, and others might find it a more of an acquired taste they grow to like as they read on. But I really think a lot of people will enjoy it! If you love epistolary novels or want to give one a try, A Letter to the Luminous Deep is worth a read. And I absolutely recommend this book to anyone that likes the idea of a beautiful, atmospheric, underwater world, a heartwarming romance, a cozy mystery, and a unique & whimsical fantasy all rolled into one story!

Oh this was absolutely luminous (I had to). I loved this book so much. It’s charming, clever, heartwarming, mysterious, and compelling. I devoured it completely.
Not only do we have a delightful romance that we get to see unfold, but we have so many mysteries! What happened to E and Henerey? What was The Dive and why did it happen? What is The Structure? What happened during the Ridge expedition? Why is Arvist so insufferable? The epistolary format worked so well for the story. I had a goofy grin on my face as I read E and Henerey’s letters to each other. And the letters between Sophy and Vyerin kept me turning the page as they tried to untangle what happened to their siblings.
I cannot wait for the next book. I’m totally entranced and can’t wait to see where the mystery takes us next!

Many thanks to NetGalley and the publisher for the preview. All opinions are my own.

As much as I wanted to like this book, I think I liked the idea of it much more than the finished product. The writing was absolutely beautiful; however, the writing style and the fact that it was a book strictly written in letters made it very difficult for me to get interested in what was happening. I found my attention wandering often while reading. Also, the characters all seemed to have the same voice which made it hard to see them as individuals. Instead of being able to remember and differentiate among them, they all ran together and I felt as if I had to continually remind myself who was who. Overall, I can tell the writer is extremely talented; however, this book did not capture my interest and fell short of my expectations.

DNF @38%. I wanted to love this, I really did, and I think I could enjoy this in physical format if the letters were stylized and formatted and such, but on a kindle and in quick succession this is almost academic work. The letters feel scholarly, which makes sense, but with such little context behind the world and the politics and academia and the people and the events that started this book off, even... it's awfully slow and difficult to push through. Will pick up a copy when it releases physically to leave on my nightstand and read a bit before bed each night, assuming my formatting wishes come true and it's not simply formatted like a regular book, but I don't think I can manage this on kindle, sorry.

The premise of this book seemed fun and interesting, but unfortunately I wasn’t able to get through it. The writing style ended up being more boring than interesting. I appreciate the opportunity to read and review it though!

First of all…gorgeous cover! Intriguing premise and a cast of exasperating and endearing characters. Romance, mystery, family dynamics, mental illness and underwater adventure…all told through a series of letters, penned by the various characters. While clever and often witty, this writing style sometimes diminished the impact of the action. The very nature of consistently being “told” in letter form what transpired, coupled with the overly verbose manner of speaking reflective of this erudite society, eventually became a bit tedious. Toward the end, I was skimming for the pertinent details, rather than enjoying every word. I’m afraid it put me off to the degree that I’m not invested enough to pursue the sequel.

Thank you to the publisher and NetGalley for this e-ARC in exchange for an honest review. Can I just say what a breath of fresh air this book was? Everything about this story was beautiful and unique. I loved the letter format of dialogue, it made me feel like a detective sifting through notes to piece together a story which only added to the immersion of the plot as we hunt for the missing persons. Genuinely, the only thing that could have made this better would be a hand drawn map. I would have loved to reference locations as we made our way around the ocean sites. I cannot believe I don’t already have the second book in my hands, I will be waiting most impatiently to see what happens next.

“A Letter to the Luminous Deep” is an immersive view into the curious life of two scholars from distanced water dwellings. I loved putting the pieces together from the various letters to understand the world-building and the mystery. This story is told through many letters between characters and does not follow a direct narrative writing style. I think for that reason, others may not enjoy it as much as I did. This tale is a charming and heart-warming low-stakes fantasy (that becomes higher-stakes towards the end). I loved it and I cannot wait to see what comes next!

For those who love:
🌊 Ocean Setting
🌊 Marine life
🌊 Epistolary Romance
🌊 Cozy Fantasy
🌊 Slow Burn
🌊 Light Academia

Many thanks to the publisher and NetGalley for the opportunity to read this ARC in exchange for an honest review.

This is an epistolary debut fantasy novel. It was set in world centered on oceans. The novel was slow and it only picked up in the last third for me. What kept me reading was that the characters and their relationships. Everyone was likeable and there were developed romantic and platonic relationships. The book seemed to be a set up for a sequel or series. The ending did leave me intrigued but I am unsure if I will continue. As someone who likes epistolary novels and classics, this book’s prose and style was a lot. The floral and almost overwrought writing prose is not for everyone.

Living in her family’s underwater home, Deep House, E. Cidnosin is a recluse who strikes up a relationship with Scholar Henerey Clel via letter. When E. and Henerey later disappear, their siblings connect to try and figure out what happened. But while seeking the answer they’ll uncover only more questions.

This story is written entirely in the format of personal journals and messages back and forth between the characters. I initially had difficulty getting into the flow of the writing. The prose is a bit antiquated as well, which took some getting used to. The world the author created is unique, whimsical, and beautiful. As I progressed through the story and got to know the characters better the pace of the plot really picked up. By the end I was very invested and was bummed to see it end!

This book is hard to summarize. It really took a turn about 75% of the way in, and the setting and terminology was unique. And do you see this cover art? Beautiful! Definitely a slow start, but worth the read for lovers of mystery and fantasy.

Thank you to the publisher and NetGalley for the opportunity to read this.

I wanted to DNF but because it’s an ARC I wanted to make sure I could judge it fully. You don’t find out the actual answer until 80% in to the book (spoiler below for the DNF people). And even then, it’s not explained much and takes a second to understand what they mean. The entire thing is Episotlary, but it’s heavy academic terminology/language, Victorian era language prose, and the four characters that are writing (past and present) all sound the same “voice” when writing. This would have been a 4/5 star if it was prose. Wasted potential of an interesting world and concepts.

SPOILER FOR REASON THEY DISAPPEARED:
So at about 80% you find out the E and Henerey left because they found a structure, where it’s an old relic of the past before they lived in sunken cities. It’s a doorway, quite literally a portal to a different world and when they went through, it exploded. So book 2 is the partners/siblings probably trying to go find them.