Who was the first poet in human history? What is the secret of Gioconda's smile? Who is depicted in the center of the Sistine Chapel? What do the words "Horse! Horse! The whole kingdom for the horse!"? How did Andrei Rublev sign the Trinity? What does Caravaggio's Lute Player sing? You will find answers to these and many other questions in Alexander Shapiro's book Riddles of the Old Masters.