In a reconstruction of the theories of Freud and Klein, Sebastian Gardner asks: what causes irrationality, what must the mind be like for it to be irrational, to what extent does irrationality involve self-awareness, and what is the point of irrationality? Arguing that psychoanalytic theory provides the most penetrating answers to these questions, he rejects the widespread view of the unconscious as a 'second mind', in favour of a view of it as a source of inherently irrational desires seeking expression through wish-fulfilment and phantasy. He meets scepticism about psychoanalytic explanation by exhibiting its continuity with everyday psychology.