Richard Feynman was the most famous physicist in the world. Only an infinitesimal part of the general population could properly understand his mathematical physics, but his outgoing and sunny personality, his gift for exposition, his habit of playing the bongo drums, and his testimony to the Presidential Commission on the Challenger Space Shuttle disaster turned him into a celebrity. Richard Feynman died in 1988 after a long illness. In its obituary the New York Times described him as ‘arguably the most brilliant, iconoclastic and influential of the post-war generation of theoretical physicists’.