According to an obituary published in The New York Times, Richard Avedon's fashion and portrait photographs "helped define America's image of style, beauty and culture for the last half-century."
Avedon was always interested in how portraiture captures the personality and soul of its subject. As his reputation as a photographer grew, he brought in many celebrities and politicians to his studio and photographed them with a large-format 8x10 view camera. His subjects include (in order) Elizabeth Taylor, Buster Keaton, Marilyn Monroe, John F. Kennedy, Dwight D. Eisenhower, and Andy Warhol.
His portraits are easily distinguished by their minimalist style, where the person is looking squarely in the camera, posed in front of a sheer white background. At times, to evoke a reaction from his portrait subject, Avedon would bring up uncomfortable areas of discussion or asking them psychologically probing questions. Through this technique he would produce images that revealed aspects of his subject's character and personality that were not typically captured by others.
Richard Avedon's website
via [Who Designed It?], [Wiki]