This fascinating story reveals radically different perceptions of madness and approaches to its treatment, from antiquity to the present day. Roy Porter explores what we really mean by 'madness', covering an enormous range of topics from electric shock therapy to sexual deviancy, witches to creative geniuses, and psychoanalysis to Prozac. The origins of current debates about how we define and deal with insanity are examined through eyewitness accounts of writers, artists, those treating patients, and the mad themselves.