Raymond Smullyan's book is probably the most fascinating collection of logic problems. About three hundred problems of varying difficulty are grouped into sections, the heroes of which are Knights and Liars, Alice in Wonderland, Bellini and Cellini, and even Count Dracula himself! If a person says: “I’m lying,” is he telling a lie? Why do physicists and mathematicians solve problems differently? How to prove anything? For everyone who wants to learn to reason.