Preface T he Guest Editors describe, in their introduction to this European Respiratory Monograph (ERM), a number of reasons why fewer and fewer new drugs receive regulatory approval, although the funds invested by the pharmaceutical industry for drug development are higher than ever before. Two main reasons are mentioned. First, the phase II and III studies, which are essential for final approval by the regulatory authorities, are extremely expensive and there is no guarantee that the development costs can be recouped after marketing authorisation. Outcome parameters of early clinical trials that demonstrate a high reliability for predicting results in phase III studies are important. However, the classical outcome parameters, such as lung function measurement and symptom scores, have failed in this regard. Secondly, drug development has stalled because targets for development are lacking. New trial outcome parameters can contribute to new target identification for therapy: targets that had not been thought of when using the classic method of drug development. I want to congratulate the Guest Editors, Martin Kolb and Claus F. Vogelmeier, for setting up this extraordinary issue of the ERM. For a topic like this, most of the authors did not have a template, and the collation of the data involved substantial work and was sophisticated. Due to time constraints, it was not possible to cover the entire field of pulmonary medicine, and there are additional areas of clinical trial outcomes that might have been included in this issue if preparation time had been available. Nevertheless, this issue of the ERM should be of interest for a wide readership, including basic researchers and clinicians in the field of pneumology and also people working in the pharmaceutical industry or in regulatory authorities dealing with drug approval. I am convinced that they will find this Monograph useful for further consideration of clinical trials. Eur Respir Monogr 2013 62: v. Copyright ERS 2013. DOI: 10.1183/1025448x.10011513. Print ISBN: 978-1-84984-044-6. Online ISBN: 978-1-84984-045-3. Print ISSN: 1025-448x. Online ISSN: 2075-6674. v