This is the first major biography, now in English, of Martin Heidegger (1889--1976) in many years. In his portrait of the philosopher, Guillaume Payen draws on previously untapped sources such as Heidegger's personal letters and his notorious Black Notebooks, written between 1930 and 1970. Payen chronicles the developments in Heidegger's life as "changing destinies," beginning with his upbringing in an uncompromising Roman Catholic family in Me kirch, Germany, and progressing through his years as a student of theology at the University of Freiburg, his break with Catholicism in 1919, his election to a professorship in philosophy at the University of Marburg, his publication of Being and Time, his becoming Edmund Husserl's successor and later rector at the University of Freiburg, his membership in the Nazi Party from 1933 to 1945, and his slow rebirth as a "great thinker" following his denazification. The result is a portrait of light and shadow.