Daughter of the Deep is a middle grade fantasy-adventure novel by Rick Riordan. The book was published on October 26, 2021, by Disney-Hyperion. The book is a New York Times best seller. Unlike Riordan's earlier books which dealt with mythology, Daughter of the Deep is a Retrofuturism science fiction novel set in a contemporary timeline of the world of Jules Verne's books Twenty Thousand Leagues Under the Seas and The Mysterious Island. This is a derivative work, featuring machinery, tools and settings described in Verne's books, and characters who are descendants of Verne's characters. It combines both old and future technologies, melding together elements of both steampunk and artificial intelligence. The book incorporates the tropes of sibling rivalry and the recovery of lost ancient tec