How do clinical psychiatrists arrive at their diagnostic conclusions? Little attention has been directed to this question by philosophers of psychiatry. Adrian Kind presents a systematic, in-depth philosophical investigation into this question and argues that psychiatric diagnostic reasoning can be understood as a model-based reasoning procedure analogous to scientific model-based reasoning. To support this, he draws on ideas from the philosophy of science, psychiatry, cognitive science, and artificial intelligence. This study is an invaluable resource for practicing psychiatrists, philosophers interested in psychiatry, and researchers in artificial intelligence or cognitive science interested in medical cognition.