Tularemia is an endemic zoonotic infection caused by Francisella tularensis, which primarily causes infection in humans who have handled contaminated animal tissue or have been bitten by infected arthropods. Because of its ease of dispersion and transmission and its high degree of infectivity, F. tularensis is also considered to be a bioterrorism agent. Consequently, there is renewed interest in the development of safe, effective measures, such as vaccines, to prevent the morbidity and mortality associated with aerosol exposure to F. tularensis. Current efforts, however, are hampered by the lack of an animal model that faithfully reproduces human infection. Employing a model of "induced human infection" with aerosol administration of F. tularensis, Dr. Theodore E. Woodward and colleagues pioneered the clinical studies of tularemia vaccines that form the basis for current tularemia vaccine research.