One of the challenges for historical biographers is to decide how far it is appropriate or legitimate to try to psychoanalyse their subject. On the face of it, such analysis might seem an obvious part of the biographical enterprise in a twentieth-century context. We are all heirs to the revolution in thought brought about by Freud's discovery of the unconscious in the nineteenth century, since when it has become commonplace that beneath people's conscious thoughts and statements lie deeper, more fundamental drives and motives, of which they are not aware and which are not under their conscious control. Indeed, speculation about such subconscious desires and impulses is normal in day-to-day conversation: this reflects and is reflected by the fact that words that originated as technical, psychoanalytical terms have become part of the general language, such as ‘neurotic’, ‘paranoid’, or even ‘death wish’ and ‘Oedipus complex’.