Cade's identification of lithium for manic-depressive illness--the prospector who found a gold nugget.

John Cade's identification of lithium as a treatment of manic-depressive illness has been judged as a landmark biomedical advance and as an initiator of modern psychopharmacology. His personal background, interests, character, experiences, and key observational skills are sketched to provide the background and logic for his discovery and to argue against his simple self-description as a clinician administrator. The Cade story illustrates the potential strengths of clinical research whereby the clinician observes "signals," formulates hypotheses and explanations, and then pursues or encourages their validity and application. The suggestion that Cade simply "rediscovered lithium" is rejected.