A thrilling new novel exploring how memory shapes the soul, by "an astonishing storyteller" (Financial Times) Software prodigy Josie Ashkenazi has invented a program that records everything its users do. When an Egyptian library invites her to visit as a consultant, her jealous sister Judith persuades her to go. But in Egypt's postrevolutionary chaos, Josie is kidnapped--leaving Judith free to usurp her sister's life, including her husband and daughter, while Josie's talent for preserving memories becomes her only hope of escape. A century earlier, Solomon Schechter, a Cambridge professor, hunts for a medieval archive hidden in a Cairo synagogue. What he finds will reveal the power and danger of the world Josie's work brings into being--a world where nothing is ever forgotten. Interweaving stories from Genesis, medieval philosophy, and the digital frontier, A Guide for the Perplexed is a spellbinding tale sure to bring a vast new readership to the acclaimed work of Dara Horn.