Preface The view on treatment of patients with severe respiratory disorders in general, and of patients with severe chronic obstructive pulmonary disease in particular, has changed during the past decades. The former, often nihilistic, approach has changed into an attitude towards more active engagement in, and treatment of, severely ill patients. In this context, noninvasive ventilation (NIV) has been brought into focus as a valuable alternative treatment, both in acute respiratory failure and chronic respiratory diseases. The growing interest in NIV has been reflected in the European Respiratory Monograph (ERM) through the years and the present issue on NIV is a comprehensive review of the field. It updates areas that were covered in the previous 2001 ERM edition and adds a number of new aspects on how NIV may be an option in the treatment of patients with primary respiratory and nonrespiratory disorders. In the current issue there are new chapters on treatment of acute and chronic respiratory failure in obese patients. Acute respiratory failure in immunocompromised patients has been given its own chapter and there are specific chapters on the use of NIV in pre-hospital patients and in palliative care. Furthermore, treatment of cardiogenic pulmonary oedema with NIV has a devoted chapter. The present updated and extended ERM on NIV, written and edited by the most appreciated experts in the field, is a must for every clinician who makes contact with patients who suffer from acute or chronic respiratory failure, in whom NIV may be considered. This issue will certainly constitute a highly appreciated source of information and knowledge, both for clinicians and scientists. K. Larsson Editor in Chief Eur Respir Mon, 2008, 41, viii. Printed in UK - all rights reserved. Copyright ERS Journals Ltd 2008 European Respiratory Monograph ISSN 1025-448x. viii