Hervey Milton Cleckley (1903 – January 28, 1984) was an American psychiatrist and pioneer in the field of psychopathy. His book, The Mask of Sanity, originally published in 1941 and revised in new editions until the 1980s, provided the most influential clinical description of psychopathy in the twentieth century. The term “mask of sanity” derived from Cleckley’s belief that a psychopath can appear normal and even engaging, but that the “mask” conceals a mental disorder. By the time of his death, Cleckley was better remembered for a vivid case study of a female patient, published as a book in 1956 and turned into a movie, The Three Faces of Eve, in 1957. His report of the case (re)popularized in America the controversial diagnosis of multiple personality disorder. The concept of psychopathy continues to be influential through forming parts of the diagnosis of antisocial personality disorder, thePsychopathy Checklist, and public perception.
In 1941, Cleckley authored his magnum opus The Mask of Sanity: An Attempt to Clarify Some Issues About the So-Called Psychopathic Personality. This became a landmark in psychiatric case studies and was repeatedly reprinted in subsequent editions. Cleckley revised and expanded the work with each edition published; the second American edition published in 1950 he described as effectively a new book.
The Mask of Sanity is distinguished by its central thesis, that the psychopath exhibits normal function according to standard psychiatric criteria, yet privately engages in destructive behavior. The book was intended to assist with detection and diagnosis of the elusive psychopath for purposes of palliation and offered no cure for the condition itself. The idea of a master deceiver secretly possessed of no moral or ethical restraints, yet behaving in public with excellent function, electrified American society and led to heightened interest in both psychological introspection and the detection of hidden psychopaths in society at large, leading to a refinement of the word itself into what was perceived to be a less stigmatizing term, “sociopath“.