The history of the vaccination of humans against rabies is ancient and curious. Dramatic success in the immunoprophylaxis of rabies was claimed over 100 years ago, at a time when the nature of the etiologic agent was only vaguely surmised. That claimed success was all the more remarkable because the first vaccine regimen proposed by Louis Pasteur was, uniquely, based upon the stimulation of an active immune response after the initiation of the infection, a procedure alleged to be reasonable because of the frequently prolonged incubation period of the disease and the usual ability to document the time of exposure to the animal bite.