There is a deep tradition of infectious diseases at Johns Hopkins. William Henry Welch’s microbiologic work included discovery of Bacillus welchii (now Clostridium perfringens) as the cause of gas gangrene, as well as studies of pneumonia, diphtheria, and other infectious diseases [1]. He was the first chair of Pathology at Johns Hopkins and the first director of the School of Hygiene and Public Health. William Osler was also a leader in infectious diseases and dedicated major sections of the Practice of Medicine to the diagnosis and management of infection [2]. Among other infectious disease leaders at Johns Hopkins, TH Gilchrist described North American blastomycosis in 1894, GH Whipple reported on intestinal lipodystrophy in 1907 (later known to be from Tropheryma whipplei), and TP Sprunt and FA Evans published a study of infectious mononucleosis in 1920 [3–5]. Infectious diseases was first administratively distinguished at Johns Hopkins in 1956, when the then–Chairman of Medicine, Dr A. Magee Harvey, asked Ivan Bennett to head a new Division of Allergy and Infectious Diseases. Dr Bennett was a quintessential physician-scientist, having made substantial contributions to the understanding of how infectious agents, primarily gram-negative organisms, interact with host defense systems to produce fever and septic shock [6]. Dr Bennett stayed at Hopkins but became the Director of Pathology from 1958 to 1969. He recruited Dr Leighton E. Cluff (Director of Infectious Diseases, 1958–1966), known for his work detailing endotoxin as well as the epidemiology and pathogenesis of Staphylococcus aureus [7]. At various times the division included infectious diseases “notables” such as Robert Petersdorf, Edward Hook, Robert Wagner, Philip Norman, Paul Hoeprich, John Perry, Robert Fekety, Joseph Johnson, Richard Reynolds, and James Allen. Following Leighton Cluff, continuing leadership was provided by Charles Carpenter (Director, 1966–1969), who directed the Cholera Research Program at Johns Hopkins and subsequently became a global leader in human immunodeficiency virus (HIV)/AIDS. He was followed by William B. Greenough (Director, 1970–1976), who pioneered studies of the physiology and lifesaving treatment of cholera using oral rehydration. By 1976, the leadership activities of the division were distributed among 3 professors with abiding research and clinical interests in infections, but interestingly 2 with primary appointments in other departments: Dr Patricia Charache (Pathology), Dr Dianne Griffin (Medicine), and Dr Patrick Murphy (Microbiology). After 4 years of running the division smoothly, the “troika” decided that they needed to resign in order to prompt the Osler Chair of Medicine, Dr Victor McKusick, to sign on a new chief of the Infectious Diseases division. In 1980, John G. Bartlett was recruited to lead the Division as the Stanhope Baynes Jones Professor of Medicine.