Medical historian Porter authoritatively traces how Western culture has explained and treated insanity. Holes bored in 7,000-year-old skulls indicate the earliest assessment of madness as spirit-possession. The ancient Greeks and medieval and Renaissance philosophers influenced by them replaced possession with irrationality as the cause of madness and exorcists with physicians as its curers. The Enlightenment stressed folly as the mark of madness; romanticism reacted by considering genius akin to madness. Asylums arose to secure the insane for their own good, and newly emergent psychiatry developed several ostensibly successful asylum strategies. As asylums became overloaded with incurables, however, disillusionment induced underfunding. Freud and his spawn came to psychiatry's rescue, but madness persists despite a century of psychoanalysis and of listening increasingly to what the insane say about their conditions. New drugs quash symptoms but have undesirable side effects, including dependency. Meanwhile, the medical profession is divided about the legitimacy of psychiatry.