Book excerpt: This issue of Clinics in Chest Medicine is Guest Edited by Peter J. Barnes FRS, FMedSci from Imperial College London and will fosus on COPD. Article topics include epidemiology, pathophysiology, cellular and molecular mechanisms and comorbidities of COPD, diagnosis and phenotype of COPD, pulmonary rehabilitation, asthma and COPD, biomarkers, bronchodilators, non invasive ventialtion, and new drug therapies.