Legionellosis is a text in two volumes that presents the modern viewpoint of the agent and the disease. It also chronicles the history of the discovery of Legionella pneumophila. Volume 1 discusses current aspects of the microbe including taxonomy, morphology, biochemistry, and physiology. It also discusses the illness including clinical features, pathology, and therapy. Volume II details the laboratory diagnosis, epidemiology, and pathology. The contributors are amongst the most eminent scientists in their respective fields.