Evarts Ziegler, 74, a literary agent whose clients included Joan Didion, John Gregory Dunne, Robert Towne, Richard Donner, Philip Kaufman, Terrence Malick, Sydney Pollack and Mario Puzo. Ziegler negotiated one of the largest prices ever paid for a film script when he represented William Goldman in the sale of “Butch Cassidy and the Sundance Kid” to 20th Century Fox. Son of booksellers, Ziegler studied at Princeton, wrote the old “Talk of the Town” column for Esquire magazine and came to Los Angeles after serving with the Office of Strategic Services during World War II. He helped found a talent agency, which later merged with International Creative Management. In Los Angeles of cancer on Saturday.