ERS | monograph Preface Robert Bals The disease area of bronchiectasis has experienced something of a renaissance in recent years. The disease’s aetiology, as well as the diagnostic and therapeutic approaches have been much better defined. These advances are clinically important as they help the diagnosis and treatment of patients with chronic cough, a frequently reported condition. The recent developments also highlight the heterogeneity of bronchiectasis, which often requires complex diagnostic tests. Therapy is also multilayered and combines strategies learned from conditions such as chronic obstructive pulmonary disease and cystic fibrosis. This ERS Monograph provides the reader with broad and detailed overview of the biology of and clinical approach to bronchiectasis. It provides in-depth information about multiple aspects of the disease area, and includes chapters covering basic biology and mechanistic areas, as well as microbiome analysis. Diagnostic approaches to comorbidities and specific phenotypes are also discussed, as well as multidisciplinary therapeutic approaches, such as antibiotic therapy, physiotherapy and specific therapies for known causes of bronchiectasis. The Guest Editors, James D. Chalmers, Eva Polverino and Stefano Aliberti, have brought together leading authors to create a book that will prove an essential resource for those working with bronchiectasis patients or conducting research in this area. I would like to thank them for their hard work I feel sure that their book will help generate advances in diagnosis and therapy, as well as better care for bronchiectasis patients. Copyright ©ERS 2018. Print ISBN: 978-1-84984-097-2. Online ISBN: 978-1-84984-098-9. Print ISSN: 2312-508X. Online ISSN: 2312-5098. https://doi.org/10.1183/2312508X.10025218 ix