February 19, 2002 Dr. Snyder was a pre-eminent Professor of Population and Public Health, Emeritus, Harvard School of Public Health where he had served as its Dean from 1954 to 1971. He was my friend and mentor. A spirited yet soft-spoken giant of a man, I came to know him because of his vast experience regarding the ability of lice to transmit disease and because of our mutual interest in the life and work of the late Dr. Hans Zinsser. Upon diagnosis of his own terminal illness, Dr. Zinsser, with access to scientists around the world, chose John Snyder as the one he wanted to continue his laboratory work on typhus. As Dr. Snyder once wrote in a letter to me, “Dr. Z asked me if I would give up my Harvard Fellowship in order to work for the Rockefeller Foundation and learn as much as …