Introduction R.A. Floto*,# and C.S. Haworth# *Cambridge Institute for Medical Research, University of Cambridge, and # Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge, UK. Correspondence: R.A. Floto, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK, Email: arf27@cam.ac.uk Since its first description in the 19th century, bronchiectasis remains a clinically important, but poorly understood condition. This issue of the European Respiratory Monograph (ERM) brings together contributions from leading international experts on the subject of non-cystic fibrosis (CF)-associated bronchiectasis in adults. This issue of the ERM discusses the epidemiology and aetiology of the condition and describes the associated changes in histopathology and radiology. It explores the basic mechanisms controlling lung inflammation and immunity and how these can be disrupted to trigger bronchiectasis. In this Monograph, we define appropriate investigation algorithms, explore the role of bacteria, viruses, fungi and nontuberculous mycobacteria, and discuss the specific features of bronchiectasis associated with ciliary dyskinesias, channelopathies, inflammatory bowel disease, immunodeficiencies and autoimmune disease. This Monograph details the various treatment modalities available for bronchiectasis, including antibiotic regimens, the use of macrolides and other anti-inflammatory agents, airway clearance strategies and the role of surgery. This issue of the ERM offers a comprehensive and cutting edge review of non-CF-associated bronchiectasis and provides a definitive guide to the management of this challenging condition. Eur Respir Mon 2011. 52, vii. Printed in UK – all rights reserved, Copyright ERS 2011. European Respiratory Monograph ISSN: 1025-448x. DOI: 10.1183/1025448x.10004911 vii