John Swenson, a multi-talented journalist who counted Thoroughbred racing among his beats, died Monday at his home in Brooklyn after a long battle with cancer. He was 71. The Brooklyn native covered racing and the New York Rangers for the wire services Reuters and United Press International, before working for the New York Post as a reporter and handicapper in the 1990s. He also worked as a free-lance correspondent for Daily Racing Form, covering Fair Grounds in New Orleans, where he also had a home. While Swenson was a familiar figure in racetrack press boxes, he cast a much larger presence in the world of rock journalism. For over 50 years, Swenson was one of its pre-eminent critics. He was most prominent during the 1970s, the heyday of the rock and roll press, and was a principal record reviewer and editor for magazines such as Rolling Stone and Crawdaddy. He also wrote seminal biographies of Bill Haley and The Who, as well as several other prominent artists, and compiled and edited three major record guides for Rolling Stone Press. Swenson is survived by his wife, Barbara Mathe, and his brother Edward.