Prisoners, Lovers, and SpiesThe first history of invisible ink revealed through thrilling stories about scoundrels and heroes and their ingenious methods for concealing messages. 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