I highly, highly recommend A Letter to the Luminous Deep (2024) and A Letter From the Lonesome Shore (2025) by Sylvie Cathrall, especially if you like epistolary novels, academic fantasy, and the idea of an underwater world created by the ancestors. I listened to them both, and recently found out that Luminous Deep was a finalist for the Libby Audiobook of the Year for 2025–it was read by four different actors, and I could not stop listening.
So the premise of Luminous Deep is that scholar of wayfinding, Sophy, and ship captain Vyerin, are dealing with the disappearance and presumed death of Sophy’s sister E and Vyerin’s brother Henery. E lived in the Deep House, a house built on the ocean floor next to a reef, by her mother who died several years ago. E dealt with a mental disorder like obsessive-compulsive disorder or severe anxiety–she had a hard time dealing with strangers or leaving her home at all, while Sophy went to school and adventured into places few others could go. Henery was a scholar of natural history, having written a book that E read, and E is compelled to write to Henery to tell him about some unusual fish she observed outside a window of the Deep House. Henery is no stranger to anxiety himself, but was also fascinated by the Deep House as a child and happily writes back to E.
After E’s and Henery’s disappearance, Sophy and Vyerin write to each other and exchange the correspondence from their siblings in an attempt to see if they can figure out what happened. It turns out that E and Henery were investigating a strange structure that showed up outside the Deep House, and they may not have perished in the seaquake that destroyed the Deep House, but may have ended up “somewhere else.”
A Letter From the Lonesome Shore picks up right where Luminous Deep left off, and adds some additional archival sources from which the story is told. I hate to say much more without spoiling it, but I was fascinated!
Some interesting facts about the world–it is queer-normative. Although E and Henery and their relationship is presumed heterosexual, most of the other pairings are queer, and most partners combine their last names to create a new last name. There are very few above-water places for humans to live, and it seems that the population is also pretty small. There is not much discussion of body size or shape, so I consider it completely weight-neutral.
I will admit that I had a hard time listening to it while I was long-distance driving (and very tired), but it was great to listen to while doing any other activity, such as crafting, chores, or walking. I was charmed!
Reading While Fat 