Many things made the New Yorker successful in its heyday. The magazine showcased the work of America’s best humorists, from James Thurber and Robert Benchley to Dorothy Parker and S J Perelman. Its eccentric founding editor, Harold Ross, knew how to coax good work out of his writers, even though he was fanatical about fact-checking. (Thurber recalled that if the Empire State Building were mentioned in a piece, Ross would not let it run until someone had called to verify that it was still standing.) The magazine could count on an audience ripe for its signature wit and sophistication. As F Scott Fitzgerald wrote, ‘New York had all of the iridescence of the beginning of the world … there was gala in the air.’ But what ultimately made the magazine a hit was its cartoons, and the greatest of its cartoonists was Peter Arno.