INTRODUCTION J-F. Muir*, N. Ambrosino#,", A.K. Simonds+ *Pneumology and Respiratory Intensive Care Unit, Rouen University Hospital, Rouen, France, # Pulmonary Diseases and Respiratory Intensive Care Unit, Cardio-Thoracic Dept, University Hospital Pisa, Pisa, and " Weaning and Pulmonary Rehabilitation Unit, Auxilium Vitae, Volterra, Italy, and + Academic Unit of Sleep and Breathing, Royal Brompton Hospital, London, UK. Correspondence: J-F. Muir, Service de Pneumologie et Unite ´ de Soins Intensifs Respiratoires, Ho ˆpital de Bois-Guillaume, CHU de Rouen, 76031 Rouen, France. Fax: 33 232889000 E-mail: jean-francois. muir@chu-rouen.fr In August 2001, the first edition of a European Respiratory Monograph (ERM) devoted to noninvasive mechanical ventilation (NIV) was published [1]. Now is a good time for a second edition, in order to take into account and consolidate views on the numerous developments that have occurred on a variety fronts. NIV is not a recent concept, having been developed in the 19th century. Subsequent milestones date from the 1950s, with the iron lung in the polio era the 1960s, with the first attempts at mask ventilation the 1970s, when mouth ventilation was used increasingly and the 1980s, when nasal interfaces improved and pressure support ventilation emerged. The 1990s and the first decade of the 21st century have highlighted the importance of pressure support ventilation and of sleep investigation in respiratory medicine, and have demonstrated the changing profile of the underlying causes of chronic and acute respiratory failure, the disease of this century, in particular the growing burden of morbid obesity. The current ERM has been thoroughly renewed and rewritten. We hope that it will afford medical teams daily confronted with acute and chronic respiratory failure a substantial overview of the new aspects of NIV, including pathophysiological indications, technology and monitoring. It is essential that these developments are understood if, over time, we want to improve survival and also optimise ventilator– patient interaction and health-related quality of life. We would like to warmly thank all the contributors for their enthusiasm and hard work and, in addition, acknowledge K. Larsson (Editor in Chief) and the European Respiratory Society Publications Dept for their excellent technical help. References 1. Muir JF, Ambrosino N, Simonds AK, eds. Noninvasive Mechanical Ventilation. Eur Respir Mon 2001 16. Eur Respir Mon, 2008, 41, ix. Printed in UK - all rights reserved. Copyright ERS Journals Ltd 2008 European Respiratory Monograph ISSN 1025-448x. ix