This book deals with the challenges faced in diagnosis and treatment of pulmonary infections, which are a cause of significantly high morbidity and mortality across the globe. Originating from bacteria, viruses or fungi, respiratory contagions account for a requirement of thorough awareness of latest progress in their pathogenesis. Progress in comprehending the immunopathogenesis of Acinetobacter baumannii infection shows how an uncharacteristic organism can cause these infections. The diagnosis and remedy of dormant tuberculosis remains a serious challenge. Hence, latest advancements in diagnosis and remedy of dormant tuberculosis have been presented in this book. There is a special case study of pulmonary non-tuberculous mycobacterial infections in the State of Pará in northern Brazil. Due to challenges faced in their diagnosis, non-tuberculous mycobacterial pulmonary diseases require special understanding for their handling. The difficulties of respiratory infections in hosts with low levels of immunity have been growing in occurrence as well as in their resilience to medication. Hence, a description of the host resistance responses against pulmonary fungal pathogens becomes necessary. Hence, the insights provided in this book will be beneficial for both clinicians and experts.