In 1907, Sigmund Freud and Carl Jung began what promised to be both a momentous collaboration and the deepest friendship of each man’s life. Six years later they were bitter antagonists, locked in a savage struggle that was as much personal and emotional as it was theoretical and professional. Between them stood a young woman named Sabina Spielrein, who had been both patient and lover to Jung and colleague and confidante to Freud before going on to become an innovative psychoanalyst herself.

A solid new interpretation of the short-lived but oft-analyzed collaboration between Freud and Jung, in which the mysterious Sabina Spielrein figures prominently. Using Spielrein's correspondence and journals--discovered in the 1970's and first appearing in Aldo Carotenuto's A Secret Symmetry (1982)--Kerr traces a fascinating, credible web of influence and cross-fertilized ideas that he weaves skillfully into a record of psychoanalytic history.