Madsen tackled all sorts of non-fiction topics, including cross-country truck drivers and the CBS news magazine "60 Minutes," the Los Angeles Times.
Madsen wrote more than a dozen biographies. His first book was a short piece on director Billy Wilder in 1968. He then went on to write about directors William Wyler and John Huston, followed by books about French fashion designers Yves St. Laurent and Gabrielle Bonheur Chanel.
He also steered away from the entertainment industry to write biographies of French thinkers Andre Malraux, Jean-Paul Sartre and Simone de Beauvoir, as well as captains of industry William C. Durant and John Jacob Astor.
His most popular books were the secret-revealing Hollywood biographies "Gloria and Joe: The Star-Crossed Love Affair of Gloria Swanson and Joe Kennedy" and "The Sewing Circle: Female Stars Who Loved Other Women."
He is survived by his wife Midori and two sons from a previous marriage.