ERS | monograph Introduction Antonio Anzueto1, Yvonne Heijdra2 and John R. Hurst3 COPD is common but that does not mean it is easy to understand and manage. Our patients deserve excellent care, wherever they live. We define excellent as world-class, patient-centred, evidence-based and cost-effective multidisciplinary care from diagnosis to death. The complexity of COPD is now more widely recognised, and with that comes care directed towards each patient’s specific demographic and clinical characteristics (phenotype) or, more likely, phenotypes. We all face, in our everyday practice, areas of controversy in COPD. Evidence-based medicine is often not available. For example, how would you alter the management for a COPD patient with α1-ATD? Can COPD arise as a consequence of premature birth? How should ACOS and COPD–bronchiectasis overlap syndrome be managed? What is the value of CT in COPD? Is there a difference between a COPD exacerbation and pneumonia? It is timely, then, to consider where the current controversies in COPD may lie. Developed from an idea discussed at the European Respiratory Society International Congress in 2014, we are delighted to present this ERS Monograph at the 2015 Congress. Our international expert authors have produced a monograph that addresses the key current controversies in a way that we hope is both relevant to the clinician through the use of case vignettes, whilst illustrated by state-of-the-art science and clinical evidence. We hope you enjoy reading this Monograph recognising the described controversies and that you take these concepts back to the clinic to improve the care of patients with COPD. Fundamentally, that is why we all do what we do. We would like to take this opportunity to thank all the authors, reviewers and ERS Publications staff for their commitment and enthusiasm for the project. Copyright ©ERS 2015. Print ISBN: 978-1-84984-063-7. Online ISBN: 978-1-84984-064-4. Print ISSN: 2312-508X. Online ISSN: 2312-5098. Correspondence: John R. Hurst, UCL Respiratory, Royal Free Campus, University College London, London, NW3 2PF, UK. E-mail: j.hurst@ucl.ac.uk 1 Department of Pulmonary and Critical Care, University of Texas Health Science Center, San Antonio, TX, USA. 2 Radboud University Medical Centre, Nijmegen, The Netherlands. 3 UCL Respiratory, University College London, London, UK. ERS Monogr 2015 69: xi. DOI: 10.1183/2312508X.10007515 xi