OBJECTIVE The purpose of this article is to review the origins of the classic teaching on pulmonary tuberculosis, its evolution in the modern literature, and the evidence that led to its demise. CONCLUSIONS Use of molecular epidemiologic techniques that entail DNA finger-printing has led to the discovery that the radiographic appearance of pulmonary tuberculosis does not depend on the time since infection. It has been confirmed that the upper lobe cavitary disease typical in adults is the disease of the immunocompetent host, whereas lower lung zone disease, adenopathy, and effusions, which are uncommon in adults, are the hallmarks of tuberculosis in an immunocompromised host.