"The Island of the Day Before" is a 1994 novel by Umberto Eco, written in Italian and translated into English. It is an unusually structured novel, featuring more philosophical musing and discussion than a traditional plot.
The book takes place roughly during the 30 Years' War and Age of Exploration, when European powers struggled against each other in war, technology and exploration. The book is supposedly the diary kept by an Italian nobleman who is in a shipwreck and climbs aboard an abandoned ship. The book alternates between his backstory, and his activities on the ship, where he discovers a hidden Dominican priest. The two try to figure out where they are and how to get off the ship, while at the same time discussing the then-fashionable philosophical ideas, which pitted scholastic ideas against new concepts of infinity and change. Umberto Eco knows his intellectual history very well, and the book is a virtual encyclopedia of ideas and events of its time. But apart from the rolling and digressing narrative, and apart from the rich prose and word games, what is the plot of this book? And who are the characters? The book's main characters are the protagonist and the priest, and both are used mostly for explicating philosophical viewpoints. The plot, such as it is, is never resolved. I enjoyed this book, and felt myself drawn in, but was also disappointed that so many of its hints and ideas were never resolved, and that its characters were mostly used for purposes of philosophical dialog.