Necessity is the mother of invention: William Stewart Halsted’s addiction and its influence on the development of residency training in North America.

William Stewart Halsted developed a novel residency training program at Johns Hopkins Hospital that, with some modifications, became the model for surgical and medical residency training in North America. While performing anesthesia research early in his career, Halsted became addicted to cocaine and morphine. This paper dissects how his innovative multi-tier residency program helped him hide his addiction while simultaneously providing outstanding patient care and academic training.