This engaging presentation of our evolving understanding of the human mind and the meaning of mental illness asks the questions that have fascinated philosophers, researchers, clinicians, and ordinary persons for millennia: What causes human behavior? What processes underlie personal functioning and psychopathology, and what methods work best to alleviate disorders of the mind? Written by Theodore Millon, a leading researcher in personality theory and psychopathology, it features dozens of illuminating profiles of famous clinicians and philosophers.