A Most Dangerous Method by John Kerr
This study of Jung and Freud, the two founding fathers of psychoanalysis, suggests that the work of both men was strongly influenced by their separate relationships with Sabina Spielrein, Jung's patient and subsequent lover who later became a confidante of Freud, and that their acrimonious split was based to a great extent on the private knowledge each man had gained about the other through Spielrein.