Early psychiatrist. Was first to combine precise clinical descriptions with statistical analysis of mental illness. Was physician in chief at Salpêtrière Hospital in Paris in 1811, developing diagnostic techniques and continuing efforts to achieve humane treatment of the mentally ill. Responsible for the first accurate description of mental retardation as an entity separate from insanity. Coined the term "hallucination." His book "Des maladies mentales, considérées sous les rapports médical, hygiénique, et médico-légal" (1838) is considered the first modern treatise on clinical psychiatry, and it remained a basic text for 50 years. The book contains some of the most striking images of the mentally ill ever printed. Esquirol anticipated modern views with his suggestion that certain mental illnesses are caused by emotional disturbances rather than by organic brain damage.