PREFACE Preface Although diagnosis always begins with a careful history and physical examination and a physician is obligated to consider more than the diseased organ, testing of lung function has become standard practice to confirm the diagnosis, evaluate the severity of respiratory impairment, assess the therapy response and follow-up patients with various cardio-respiratory disorders. Ventilation, diffusion, blood flow and control of breathing are the major components of respiration and one or more of these functional components can be affected by any disorder. Frequently, no single pulmonary function test yields all the information in an individual patient and multiple tests have to be combined to allow proper evaluation of the patient. The pulmonary function laboratory is therefore very important in pulmonary medicine to provide accurate and timely results of lung function tests. The purpose of this issue of the European Respiratory Monograph is to provide up-to- date information on the application and interpretation of different pulmonary function tests in the work-up of patients suffering from cardio-respiratory diseases. In each chapter of this issue, the contributors have attempted to relate theoretical considerations of the different physiological tests to clinical application. New insights into the diagnostic approach to patients with respiratory impairment form an integrated part of the different chapters. This issue not only offers the reader a state-of-the-art approach to pulmonary function testing, but also contributes significantly to a better understanding of the pathophysiological processes underlying various diseases and contributing to the morbidity of patients. The guest editors of this issue, Henk Stam and Rik Gosselink, have done a great job in the coordination and planning of this issue of the European Respiratory Monograph. The authors of the different chapters have really tried to give the reader up-to-date information about the different lung function tests. Therefore, I am convinced that the knowledge and information provided in this issue of the European Respiratory Monograph will contribute to the best possible evaluation and care for afflicted individuals. E.F.M. Wouters Editor in Chief Eur Respir Mon, 2005, 31, vii. Printed in UK - all rights reserved. Copyright ERS Journals Ltd 2005. vii