By Winthrop Sargeant October 31, 1958 Richard Avedon at The Tuileries Gardens in Paris, France, 1956. Photograph by David Seymour / Magnum To people who are only casually interested in such matters, fashion is a bewildering phenomenon. It has been denounced as “spinach” and “a racket for selling clothes.” It constitutes, as nearly everybody knows, the third-largest industry in the country, and it is responsible for the existence of a considerable publishing business.