Curator, critic, and photographer. At the Museum of Modern Art, he served as director of the photography department for nearly thirty years. His program there set the pace in the field at a time when few institutions were interested. In more than a hundred exhibitions, he featured established or previously unrecognized photographers, as well as thematic groupings. His shows included landmark presentations of work by Diane Arbus, William Eggleston, Walker Evans, and Garry Winogrand. An elegant and perceptive writer, Szarkowski has exerted unparalleled influence on how photography is understood and discussed. His presentation of photography as an independent medium with inherent characteristics and meanings has become widely accepted. He also demonstrated that while photographs have a special and intimate relation with the world, their significance depends equally on formal qualities. A native of Ashland, Wisconsin, Thaddeus John Szarkowski began taking photographs as a child. His study of art history at the University of Wisconsin was interrupted by service in the U.S. Army in 1945–46. Upon his graduation in 1948, took a position at the Walker Art Center in Minneapolis. In 1951 he began teaching art history at the Albright Art School (now merged with the art department of the State University of New York at Buffalo), while exploring the theory and practice of photography. The Idea of Louis Sullivan (1956), his first book, combines his admiring and revealing photographs of Sullivan's architecture with texts by and about the architect. In 1962 he succeeded Edward Steichen at MoMA. Since his retirement from the museum in 1991, Szarkowski has returned to his own photography. His images of a favored subject, his upstate New York farm, appear in Mr. Bristol's Barn (1997). Earlier, he had published his own work in The Face of Minnesota (1958). Szarkowski's Looking at Photographs: 100 Pictures from the Collection of the Museum of Modern Art (1973) remains a model introduction to the principles and meanings of photography. His other books, some of which served also as exhibition catalogues, include The Photographer and the American Landscape (1963), The Photographer's Eye (1966), New Documents (1967), Mirrors and Windows: American Photography since 1960 (1978), and Stieglitz at Lake George (1995).