Henry Knowles Beecher (February 4, 1904 – July 25, 1976) was a pioneering American anesthesiologist, medical ethicist, and investigator of the placebo effect at Harvard Medical School.Beecher's influential 1966 article on unethical medical experimentation in the New England Journal of Medicine — "Ethics and Clinical Research" — was instrumental in the implementation of federal rules on human experimentation and informed consent. A 1999 biography—written by Vincent J. Kopp, M.D.