Praise for Sylvie Cathrall: "This book is not shaped like a book, and I mean that as a compliment. It is instead an underwater treasure-chest to be slowly unpacked, full of things I adore: nosy and loving families, epistolary romance, gorgeous worldbuilding, and anxious scholars doing their best to meet the world with kindness and curiosity. Take a deep breath and dive in." --Freya Marske "Cathrall's debut caught me up on a wave of whimsy and swept me away with its charm. A story to be cherished." --Lyra Selene "A fascinating and charming story told in a uniquely elegant voice. A watery wonder of a novel! I loved it." --Louisa Morgan "A Letter to the Luminous Deep is like nothing I've read before.

The heartfelt intimacy of the epistolary narrative, juxtaposed with the magnificent oceanic world-building, results in a novel that is at once deeply human and mind-bogglingly imaginative. Both the setting and the story are exquisite, but it was the lovingly crafted voices of the characters that kept me hooked from beginning to end." --Megan Bannen "A shimmering, delicately crafted delight of a book, steeped in love for the wonder of nature and the vagaries of archival research. Readers looking for heartwarming romance and scholarly mystery against the backdrop of a wildly imaginative world will be charmed." --H. G. Parry " With its gorgeous underwater setting and whimsical academic sensibility, A L etter to the Luminous Deep is a strange, epistolary wonder." --Mary McMyne.