Prisoners, Lovers, and Spies is a book about concealing and revealing secret communications. It is the first history of invisible writing, uncovered through stories about scoundrels and heroes. Spies were imprisoned or murdered, adultery unmasked, and battles lost because of faulty or intercepted secret communications. Yet, successfully hidden writing helped save lives, win battles, and ensure privacy; occasionally it even changed the course of history. Kristie Macrakis combines a storyteller's sense of drama with a historian's respect for evidence in this page-turning history of intrigue and espionage, love and war, magic and secrecy. From the forum of ancient Rome to the spy capitals of the Cold War, Macrakis' global history reveals the drama and importance of invisible ink. From Ovid's advice to use milk for illicit love notes, to John Gerard's dramatic escape from the tower of London aided by orange juice ink messages, to al-Qaeda's hidden instructions in pornographic movies, this book presents spellbinding stories of secret messaging that chart its evolution in sophistication and its impact on history. An appendix includes fun kitchen chemistry recipes for readers to try out at home.