Susan Sontag (1933-2004) spoke of the promiscuity of art and literature--the willingness of great artists and writers to scandalize their spectators through critical frankness, complexity, and beauty. Sontag's life and thought were no less promiscuous. She wrote deeply and engagingly about a range of subjects--theater, sex, politics, novels, torture, and illness--and courted celebrity and controversy both publicly and privately. Throughout her...