Oh how I was so excited for this book and wanted to love it... but it just fell short for me. I wanted to be captivated by the underwater world and the mystery surrounding the disappearences but each letter just seemed so dull. Some of the imagery was exquisite and I think other readers could appreciate this story for what it is but it ultimately just fell flat for me. The cover is absolutely gorgeous though.

This is one of the most unique books I’ve read, largely because the entire book is made up of letters and focuses on a past event that the characters are trying to piece together. While I’m glad I started reading it on kindle to figure out who’s who, I much preferred the audiobook as the characters’ personalities were more effectively communicated as it was read. It took me awhile to get into the book, as not much actually happens. Little by little the author unveils more of the mystery until the ending when you find out what happened. At the same time, the ending leaves you with even more questions as the characters themselves are unsure what happened. If that sounds confusing, I’m sorry but you’ll need to read the book to understand lol.

Overall, it was really well written and I enjoyed the different plot lines. The mystery may have been a written a little too mysteriously for me as I’m really not sure what’s going on with E and Henerey. Additionally, the world building took a little for me to understand all the nuances to their society. However, I’m definitely hooked into the series and will continue.

I would recommend this book for fans of Emily Wilde, academia, and unique world building.

"A Letter to the Luminous Deep" by Sylvie Cathrall takes readers on a captivating journey into the depths of an enchanting mystery set at the bottom of the ocean. Through the unique epistolary format, the story unfolds like a cozy and whimsical tale, drawing readers into a world of romance, friendship, and intrigue.

The author's skillful use of letters and journal entries immerses readers in the lives of the characters, creating a rich and engaging narrative. From the sweet romance between E. and Henerey to the evolving friendships among the characters, every aspect of the story feels endearing and well-developed.

While the book's academic language and underwater jargon may slow down the reading pace for some, those willing to savor the intricate storytelling will find themselves rewarded with a truly unique and thought-provoking experience. With its blend of mystery, romance, and captivating world-building, "A Letter to the Luminous Deep" is a must-read for fans of whimsical tales and atmospheric settings.

An epistolary debut from Sylvie Cathrall about the mysteries of the sea and a slow burn romance between a poet loving scholar and a shy shut in sounds like the perfect recipe for me, but it didn't quite land.
I liked a lot of this. The letters between Henerey and E. were sweet and fun, and I enjoyed Sophy and Vyerin trying to solve the mystery of what happened to their siblings a year prior by pouring over letters and diary entries. The world building was interesting and there was a mystery at the root of the story. That mystery is what kept me going past the 30% mark, when I wanted to give up.
I loved the last quarter of this book. Everything came together and mysteries were solved and the book set up for volume 2. But I felt like a lot of this book could have been glossed over. I also had a hard time picturing a lot of what was described and wanted more sketches throughout the book than what were given. At the end I still had questions over what was going on.
I'm glad I stuck it out but almost didn't. I feel if we had half of this novel and half of novel 2 together it would have been better paced and stronger overall.

Thank you to Netgalley for an ARC in exchange for an honest review.

3.5 stars.

Let me put it out there from the beginning - I really enjoyed this book, BUT (I know, I know, why does there have to be a "but") the pacing was absolutely snail-like.

Now, about the story - I think I am coming to like epistolary novels, as I enjoyed the format for this tale. However, be warned that you are not going to get a lot of the main characters' letters (E. and Henerey.) Mostly, the letters are between Vyerin and Sophy, the siblings of our lost characters. And of course, other relevant letters from side characters are scattered throughout to give context and further details.

The romance in the book is resultingly very minimal. Since we are not WITH E. and Henerey, and just reading about them through letters, the romance is a distant addition. What we do see of it is sweet, wholesome, and lovely!

The setting was imaginative, frilly, and intriguing. As my half-buddy-reader Cassie mused, there is a distinct sci-fi or dystopian atmosphere to the world as you move further into the story.

The plot was compelling, but only AFTER about 70% of the story, when we move out of the set-up and worldbuilding portion of the book. Which is where my qualm comes in that the pacing was too slow - for so much of the book, we're reading letters between Sophy & Vyerin with very little information being shared about E. and Henerey or the greater mystery. Sure, I understand it takes time for the intrigue to set in, but I honestly could have gotten most of the needed plot points in the first 20% and the last 30% - HALF of the book!

However, the flip side is that the book maintains a very light academia feeling to it, with the chapters being breezy and full of frilly details that add color and dimension to the world. So, if that is to your taste, I think you will adore A Letter to the Luminous Deep!

And in case you think I found more cons than pros, I am very invested in the next book due how the mystery finally began to unspool near the end! I predict my enjoyment of book 2 will be much higher, since the more tedious ground-laying has already been accomplished.

Thank you to NetGalley and the publisher for allowing me to read an advance copy of this novel in exchange for my honest opinion. The setup of this novel took some getting used to, but once I was adjusted to that I really did enjoy the story! Being able to watch two people fall in love through letters was truly beautiful. You can tell the author had real love for all of her characters by the way they were written, and the rep for OCD and anxiety was amazing! I can't wait to see where this story goes in future works!

This was a tough one for me. I know it says so right there in the title - “letter” - but epistolary novels are not my favorite. I get stuck on the choice of format (Why make the reader, and the narrative, jump through these hoops when it would be easier to just tell the story?) and this took me a lot longer than a book of this length normally would. All that said, I liked a lot of what’s happening here: Sylvie Cathrall creates an interesting and unique world (is it ours in the future? Some other planet? It’s hard to know for sure) and sets up a compelling mystery. The main characters, E. and Henery, are both neurodivergent people who struggle to engage with the world but find remarkably kindred spirits in one another. The other two principle characters, E.’s sister Sophy and Henery’s brother Vyerin, left to try to understand their lost siblings through their letters to each other, are deeply sympathetic in their grief and desire to connect with what they’ve lost. I’ll definitely plan to pick up the sequel, but forgive me if I hope that the format can move on from letters going forward.

Thanks to NetGalley and Orbit Books for a copy of this book in exchange for an honest review.

I really hate having to devastate the whole world like this but.. this was a DNF for me. This is an underwater academia fantasy that is told through letters and interviews basically and it’s very romance. Some have called this a cozy whimsical mystery that you have to try and piece together as you read and maybe I just don't like a challenge like that. I hope this works for others though!

This story is so dear to my heart! To preface my completely biased review, I am an introverted ecology researcher with anxiety and mild OCD. I immediately felt a kinship to this cast of academically driven, letter writing, deep sea loving nerds. I enjoyed the treacherous adventures, sweet first romances, and unlikely friendships built along the way.

P.S: I sincerely hope Arvist redeems himself in future installments in this series!

P.P.S: For reviews (especially DNFers) mentioning the somewhat slow pacing, or tedious nature of correspondence used in this story, keep in mind that these are both extremely accurate elements to add for the context of post-graduate academia! The author did a lovely job, and the story is certainly worth the slow build. I encourage readers to take their time with this novel to appreciate the intricate world and all it's lovingly crafted context.

DNF 27%
I feel this is a very polarizing book. People either love it or cannot get into it. I am one of the latter, because I just did not enjoy this. I think the ideas explored and the fantasy world was very well fleshed out, even though this is told through letters, but I was not invested in any of the characters.
I also personally have never had a real hit when it comes to more cozy fantasy stories. The meandering and vibes are just never enough for me to stay engaged personally. And this story, while I definitely want to praise the writer for a debut novel of such caliber, was just a bit to meandering for me.

Big thank you to NetGalley and the publisher for allowing me to read the ARC of this novel.

I wanted very much to like this -- the description is enticing, as is Freya Marske's praise for the book -- but the archness of the language, which did charm me at first, started grating after a while. "Look at me!" it seemed to say: that is, the prose was in love with its own mannered quality, so that it got in the way of engaging with the characters and the story. When I find myself reluctant to keep reading a book whose premise is as perfectly tailored to my tastes as this, something's not working as it should.

I'm sorry I can't say anything more positive.

This book has all the sweetness and joy of discovering someone solely through old letters. As a two-for-one, you get to know both E. And Henerey, as well as their respective siblings who are trying to solve the mystery of what happened and how did things ended up the way they did.

For me, as sweet and charming as this book is, I found it too much on the slow side. The language is archaic and hard to get immersed in. While that definitely adds to the feeling of reading old letters, it also makes it challenging to feel connected to the characters. Additionally, there’s a mystery to solve but no inciting incident to hook you or conflict to help the story progress. Instead, the beauty of the story is that you really feel like you are reading old letters and discovering these characters through their own words. But because of the slow pace, you may put the book down and forget to pick it back up again.

This book starts off almost as if it should be categorized as nonfiction. Told through scholarly articles, letters and voice correspondents you learn of the lives of E. and Henerey and their mysterious disappearance. Due to the sophisticated way the letters are written I did find it to be a slow start. Once I got in the rhythm of the back and forth I became for invested in the characters and unraveling the mystery of the Deep House. If you are looking for an enchanting, whimsical novel of the ocean and it's scholars, give it a try!

Ahoy there mateys! This is an odd book to list as abandoned because I really enjoyed what I had read (25%).  I loved the format and the world building.  I loved many of the characters even though I kept getting a couple mixed up.  So much of it is fascinating.  The major issue was the pacing.  It is so darn slow.  And then I found out it was a book 1 and not a standalone like I thought.  I just couldn't continue knowing I wouldn't get enough answers.  I couldn't imagine having to read another book as slow as this one.  I like to think I will come back and finish this one if the crew reviews of the next book are excellent.  But I have to let it go for now because I am not at all in the mood to finish.  Arrr!

I want to take a moment to think the publishing company as well as NetGalley for providing me a copy of this book in exchange for a review.
The ocean is calling! This book reminded me a lot of a study and drowning so if you really enjoyed that book then you definitely need to pick this one up. It was a fun ride and it definitely kept me up late at night just so I could finish the book.

I had to DNF this. I really tried to get through all of it, but I just couldn't get invested enough in the story. I'll explain.

What I liked:

I really enjoyed the characters, particularly E. and her representation of mental health and quirky sibling dynamics. I also really enjoyed the concept of a book entirely in letters.

What I disliked:

The length!!! And the speed of the plot development, to be honest. In my eyes there are two plots in this book -- the romantic subplot between E. and H., and the "mystery" subplot surrounding what E. finds outside her underwater home. I made it through 40% of the book, and both of these had JUST barely started to get developed. Most of the remainder about the book felt like letters between other family members and history of this underwater civilization...on Earth (I think?) many years into the future. If this book had been split up multiple short novels I think it would've read much better. I just got tired of chasing a buried lead that took forever to circle back. At some point I had to just skip ahead... which was more evidence that the bulk of the book was not necessary to the story.

I really wanted to love this but it was not for me.

Wow this book was like nothing I’ve read before!

E. And Henerey relationship blossoms through letters alone, but when they disappear it’s up to their siblings to try and find out what happens.

This book is written entirely through letters and the world and characters still managed to be fully immersive and intriguing.

I will admit this one took me a little while to connect with and really understand what was going on, but I was able to push through the beginning and I’m so happy I did!

It was unique, fun, beautifully written, and adventurous and I can’t wait for book two! I mixed in some of the audio book here too and the narrators really brought it to life.

The writing style is pretty good and I liked the letter format. However I couldn't connect to the characters and I didn't care about E and Henerey relationship. I was interested on the world and the research they were conducting.

Thank you Netgalley, author, and publisher for the ARC.

There was so much about this that was so lovely, as well as some things that fell flat. Let’s get into it:

A Letter to the Luminous Deep is a collection of beautifully written letters, many of which between our beloved E and Henerey as they first begin to correspond and later fall in love prior to their mysterious disappearance, as well as letter between their respective siblings who are trying to discover the truth of what has happened to them.

I adored quite literally every single character we meet in this tale. I loved E and Henerey and their singular way of communicating that makes so much sense to them, but not many others. They were so incredibly charming and their love so utterly genuine and believable in how it grows. I loved Sopy and Vyerin as they work to discover what’s happened to their beloved siblings, as well as grow a deep and unflinching friendship.

The world is unlike any I’ve ever read in a fantasy book, with a human society situated atop an enormous ocean in various depth-crafts as well as on small islands, most of which host some branch of an academic institution. This is never clearly described, but rather something that the reader puts together with time. I enjoyed this in some part but also found myself wishing I knew even more about the ins and outs of the society, as well as how it came to be (which is, again, touched on but not fully delved into)

This brings me to my ultimate qualm with the story, which I will say up front may be more so a personal preference. This story is quite open-ended in a lot of ways, both with the literal end of the story but also in its world building. I found myself thinking, come the end, that the open-ended mess of E & Henerey’s fate would be more appealing if I’d understood more fully what was happening in the world around them, both at present and in the past. It still made for a completely charming and later mind-bending experience to read, but also felt… strangely incomplete. If you’re one who hates open endings, I don’t see you enjoying this. Even if you’re one who can get down with them under some circumstances, I could see you being dissatisfied with this (as I fall under this category myself). That being said, there is absolutely a type of reader who would devour this and adore it all the more for its intentionally missing pieces.

I’ll certainly be keeping an eye on this author, as I overall quite enjoyed the uniqueness of this world and story, as well as the format being so different from most other things I’ve read. I wish I had more of a concrete jumping off place to go on from that ending, but I still found a lot of value in the journey. Thank you so much to Orbit & NetGalley for this eArc!

I struggled through what I could read of this book, I might try again, but I'm not sure. I got through 30% and there isn't any story yet. I usually like epistolary novels, but this had too much science speak for me to get through. I think another type of reader would love this book because it is well written, but I don't think I was the right audience for it.