The psychologist Jonathan Shedler remembers where he was when he first realized there might be something to the psychoanalytic idea of the mind as a realm far more complex, and peculiar, than most of us imagine. He was an undergraduate, at college in Massachusetts, when a psychology lecturer astonished him by interpreting a dream Shedler had related – about driving on bridges over lakes, and trying on hats in a shop – as an expression of the fear of pregnancy. The lecturer was exactly right: Shedler and his girlfriend, whose dream it was, were at that moment waiting to learn if she was pregnant, and desperately hoping she wasn’t. But the lecturer knew none of this context; he was apparently just an expert interpreter of the symbolism of dreams. “The impact could not have been greater,” Shedler recalled, if his “words had been heralded by celestial trumpets.” He decided that “if there were people in the world who understood such things, I had to be one of them.”