This book providesa practical approach to bronchoalveolar lavage (BAL) and its analyses, which are used worldwide in both research and clinical settings. It includes useful guidelines with a theoretic background and provides details on microscopic and flow cytometric measurements for all known differential diagnostics made with BAL analyses, from chronic diseases like COPD and ILD via infectious diseases to inherited illnesses like cystic fibrosis. It includes BAL in both adult and pediatric medicine. The text is supported throughout by illustrations and clinical cases, serving as an invaluable resource for respiratory medicine and infectious disease clinicians and trainees. Key features: Uses BAL in the infectious diseases field and the search for respiratory viruses using the reverse transcription polymerase chain reaction (RT-PCR) technique. Presents contributions from worldwide experts. Clarifies the BAL technique and its diagnostic utility to respiratory physicians, cytologists, and pathologists involved in the diagnosis of pulmonary disease. Provides an updated perspective on the future applications of BAL techonology to research and clinical medicine.