The apprenticeship of an editor and the secret role of a mentor.

Dr. Alvan R. Feinstein, late editor of the Journal of Clinical Epidemiology, is remembered by his fellow editor in this article. His role is highlighted as an innovative gatekeeper of clinical and epidemiological communications and as an effective secret mentor of his younger partner. The profile of his editorial practice is summarized as "six commandments" and the Golden Rule of pursuing attainable excellence.