This book reviews the role of the lung microbiome in the development and progression of lung diseases. It deals with the role of microbiota dysbiosis in influencing host defense and immunity leading to resistance, colonization, and disease exacerbation. The book delineates the complex interaction between pathogen and lung residual microbiota during disease conditions. It further highlights the potential role of lung microbiota as the key modulator of lung carcinogenesis and immune response against cancer cells. Lastly, it reviews technological developments for unraveling the lung microbiome that profoundly impacts clinical diagnostics. This book is an essential resource for the scientists working in pulmonary diseases, pharmaceutical & clinical sciences, and pulmonary clinicians.