Career
Born in Copenhagen and raised in Paris, Madsen turned from music to writing in the early 1950s, initially for the Paris edition of the New York Herald Tribune. In 1956 he moved to Canada and began working for United Press International. He moved to Hollywood in the early 1960s and began writing biographies.
Madsen wrote on topics such as cross country truck drivers and the Columbia Broadcasting System news magazine "60 minutes".
He was best known for his biographies of Hollywood celebrities, fashion pioneers, and business titans. Biographies included Billy Wilder, Barbara Stanwyck, Coco Chanel, Greta Garbo, John Jacob Astor, Jacques Cousteau, Yves Saint Laurent, André Malraux, Jean-Paul Sartre, Simone de Beauvoir, William C. Durant, William Wyler, and John Huston.
He died of pancreatic cancer in Los Angeles at the age of 76.