In 1941, a young Romanian escaped wartime Italy, where he had recently completed a degree in architecture, and began submitting cartoons to a weekly Manhattan magazine. For the next six decades, Saul Steinberg's covers, cartoons, features, and illustrations would be a defining presence at The New Yorker. As the magazine became a standard-bearer of taste and intelligence in American letters, Steinberg's drawings emerged as its visual epitome, and the...