ERS | monograph Introduction Martin Reck1, Anne-Marie C. Dingemans2 and Virginie Westeel3 Lung cancer still represents one of the most frequent solid tumours with the highest tumour-associated mortality and increasing global incidence rates. Relevant changes have been seen in epidemiology and there have been substantial improvements in all disciplines of lung cancer treatment. However, the picture of lung cancer treatment has become quite complex, and treatment strategies are moving more and more from global treatment algorithms to individualised treatment. Standardised and adequate histological, as well as molecular classification (as it is reflected in the recommendations for ADC classification), have become crucial in order to give the individual patient the chance of optimal treatment. As well as relevant steps in surgery and radiotherapy, new impressive opportunities in systemic treatment have opened up through the identification of treatable oncogenic driver alterations and the appropriate targeted therapies. Furthermore, in 2015, after decades of negative trials, we are experiencing a fascinating phase of immunotherapy with a completely new class of agents. Of all the solid tumours, lung cancer has really demonstrated rapid and substantial progress in treatment efficacy based on major progress in diagnostics. Therefore, it is of paramount importance that the pulmonologist as key member of the interdisciplinary team is familiar with the current state of the art in lung cancer care. We hope that this issue will be of interest to all researchers, clinicians and surgeons in the respiratory field and that it will help to improve understanding about lung cancer, answering all the questions encountered in everyday practice. Copyright ©ERS 2015. Print ISBN: 978-1-84984-061-3. Online ISBN: 978-1-84984-062-0. Print ISSN: 2312-508X. Online ISSN: 2312-5098. Correspondence: Dept of Thoracic Oncology, Lung Clinic, Airway Research Center North (ARCN), Woehrendamm 80, Grosshansdorf 22927, Germany. E-mail: m.reck@lungenclinic.de 1 Dept of Thoracic Oncology, Lung Clinic, Airway Research Center North (ARCN), Grosshansdorf, Germany. 2 Pulmonology, Maastricht University Medical Centre, Maastricht, The Netherlands. 3 Service de Pneumologie, CHRU Hôpital Jean Minjoz, Besançon cedex, France. 4 Université de Franche-Comté, Besançon, France. ERS Monogr 2015 68: xiii DOI: 10.1183/2312508X.10003615 xiii