Who was Sabina Spielrein? She is probably best known for her notorious affair with Carl Jung, which was dramatized in the film A Dangerous Method, starring Keira Knightley. Yet her life story is much more compelling than just one famous relationship. Spielrein overcame family and psychological abuse to become a profoundly original thinker in her own right. Sex Versus Survival is the first biography to put her life and ideas at the center of the story and examine Spielrein's key role in the development of psychoanalysis. Drawing on fresh research into Spielrein's diaries, papers, and correspondence, John Launer shows how Spielrein's overlooked ideas--rejected by Freud and Jung but substantially vindicated by later developments in psychology and evolutionary biology--may represent the last and most important stage in the rediscovery of an extraordinary life.