Drawing from an inexhaustible source of clinical expertise, clinical research, and intellectual creativity, Alvan R Feinstein (1925–2001) became the founding father of clinical epidemiology. He was professor of Medicine and Epidemiology at Yale University School of Medicine from 1969, Editor of the Journal of Chronic Diseases (1982–1988) and founder and Editor of the Journal of Clinical Epidemiology (1988–2001). He was author of about 800 scientific publications. Most of these were full papers in peer reviewed journals, of which Feinstein was first author in most cases. Feinstein published six authoritative books. Clinical Judgment (1967), Clinical epidemiology: the architecture of clinical research (1985), and Clinimetrics (1987) were breakthroughs in clinical science, and still a breeding ground for innovation. (Photograph reprinted from Journal of Clinical Epidemiology, with permission from Elsevier Science).