A sea change has been taking place in the science of mental healthcare. Dismissed for years as a soft, unquantifiable substitute for real medicine, evidence is now piling up that therapy - psychoanalytic therapy in particular - is one of the most powerful treatments that we possess for illness of any kind. Vastly more effective than almost all psychiatric drugs, it is as reliable against a plethora of mental complaints as the HPV vaccine is at preventing cervical cancer. But why does it work so well? The answer may lie in another surprising development. The model of the human mind that is...