Originally published in 1985, this book provides a philosophical analysis of the concepts of madness and moral responsibility. It challenges the view that because they are victims of mental illness, the insane should not be blamed for actions resulting from their condition. The author urges a return to the neglected equation between madness and a want of reason, arguing that the impulse to excuse the criminally insane must be grounded in an appeal to their irrationality and unreasonableness. Through meticulous examination of the psychological states and behaviour patterns of major mental abnormalities, such as schizophrenia and depression, the author develops a notion of exculpating unreason. This is an interdisciplinary book which encompasses analytical philosophy, abnormal psychology and law.