In this issue of Clinics in Chest Medicine, guest editors Drs. David A. Kaminsky and Teal S. Hallstrand bring their considerable expertise to the topic of Pulmonary Function Testing. Leading experts provide in-depth discussions on key topics in respiratory diagnostics, including spirometry, lung volume measurement, diffusion capacity (DLCO), methacholine and mannitol challenge testing, exercise and field-based testing, cardiopulmonary exercise testing (CPET), and more.