Simone de Beauvoir, along with Jean Paul Sartre, was one of the most powerful voices on behalf of a problematic existentialist position on "crusade" for the soul of postwar France. Dr. Alice Von Hildebrand describes the influences, both intellectual and personal, on her development, and the problems existentialist visions of this sort pose for Christianity. Taken from: Crusading, the Crusader & the Christian Order - 2002 VonHildebrand Institute