For the Love of Mahler takes us into the passionate world of Henry-Louis de La Grange, a charismatic 91-year-old music historian who, since first hearing a Mahler symphony in 1945, devoted the rest of his life to researching every detail of the composer's biography. After meeting Mahler's widow Alma in 1952, his deepening friendships with Gustav and Alma's daughter Anna, and granddaughter Marina, made him a virtual member of the family. The film joins Henry-Louis on his annual migration from Marrakech to Paris and to the Italian Alps, while he busily works on revising his epic four-volume biography of Gustav Mahler. How Mahler's music inspired his life, and how Henry-Louis channeled an obsession into a lifetime of groundbreaking discoveries, famous friendships and award-winning accomplishments, demonstrates the remarkable power of music to change lives. Includes commentary by Pierre Boulez, Riccardo Chailly, Christoph Eschenbach, Thomas Hampson, Marina Mahler (the composer's granddaughter), and others.