A series of letters between Emma Jung and Sigmund Freud appear at the heart of this engaging book. They express ‘Emma’s dilemmas in a nutshell’, Catrine Clay remarks – ‘all connected to the central one: Carl’. The letters were unknown to Emma’s husband and probed perhaps deeper into Freud’s ‘amortised’ marriage (as Freud himself put it) than the Viennese psychoanalyst would have liked. They provide new shading to the famous break between Freud and Jung, which ended the former’s hopes that Jung should become his heir and plunged the latter into a transformational depression. The Jewish doctor believed that his new science of psychoanalysis could not achieve wide acceptance without a Gentile of stature beating the drum for it; but now, as Jung began declaring independence from the literalness of Freud’s sexual theories and introducing a characteristic hypothesis that incest might hide buried spiritual urges, Freud ‘felt betrayed’. He remarked that whereas he had once seen Jung as a ‘born leader’, he now saw him as ‘immature’ and ‘in need of supervision’. Emma was, among other things, trying to mitigate this reaction. It did not work.