Abstract
The concept of mental illness which Henry Maudsley developed and espoused has a special significance at this time. Psychiatry appears to have entered a new phase in its evolution as a mental science, in which its dependence on both the biological and the psychosocial disciplines is recognized, in which clinical observations are made under carefully controlled conditions, and where hypotheses lead to research rather than conclusions. This maturation was encouraged and predicted by Henry Maudsley who, more than a century earlier, had synthesized from the knowledge of his time a prospectus of psychiatric progress which anticipates much of our present thinking, often in considerable detail and striking exactitude.