INTRODUCTION J. Boe, M. Estenne, W. Weder Major advances have been achieved since the first successful lung transplantation (LTx) performed two decades ago, such that the procedure has now gained widespread acceptance as a therapeutic option for patients with severe functional impairment and limited life expectancy. This monograph will review in detail the current status of all aspects of clinical LTx. Since the early 1980s, when LTx was only proposed to patients with pulmonary vascular diseases, there has been a considerable expansion of the spectrum of diseases for which transplantation can be offered. In addition, some recipient characteristics that were previously regarded as absolute contraindications are now considered acceptable. These factors have resulted in a rapid growth of the number of potential candidates that has not been paralleled by an increase in the number of donor lungs, leading to a levelling off of the annual LTx rate, a doubling of the median waiting time and an increase in the number of candidates who die while awaiting transplantation. As a result, the procedures of patient selection, referral, and listing have evolved. Waiting list mortality may be decreased by an aggressive management of patients with advanced lung diseases, including the use of new medical treatments, such as vasodilator therapy for pulmonary artery hypertension. In addition, efforts to increase the proportion of donor lungs that will eventually be transplanted are of the utmost importance. Such efforts include optimisation of allocation policies, improved management of lung donors, the use of "marginal" donors, of lobar transplantation from living or cadaveric donors, and of organs from nonheart-beating donors. In the future, xenotransplantation may also offer a solution to the current shortage of donor organs. The last 20 yrs have witnessed substantial improvements in the preservation of the lung allograft and in surgical techniques, which now include heart-, single-, sequential bilateral- and lobar LTx. Remarkably, there has been a dramatic reduction in the incidence of bronchial anastomotic complications. The perioperative management of patients has been standardised and refined. Over the last few years, new immuno- suppressive agents have become available, and have been used in the induction and maintenance regimen of lung transplant recipients. However, the benefits that these novel agents have procured in terms of prevention of acute and chronic rejection after renal and liver transplantation have not yet been demonstrated in the setting of LTx. In fact, chronic allograft rejection manifested histologically as bronchiolitis obliterans remains the major hurdle to long-term survival its pathogenesis is only partially elucidated and its prevention and treatment are still disappointing. Yet, progress in the prevention and/ or management of infectious and noninfectious complications have resulted in improved outcomes, with an increasing proportion of patients surviving beyond 5 yrs and report- ing dramatic changes in quality of life. This favourable trend is also seen in the paediatric population. This monograph discusses the marked physiological alterations associated with LTx, their impact on pulmonary function (and cardiac function in recipients of heart-lung grafts) and on exercise capacity, as well as the future of LTx. LTx has reached its current clinical plateau largely through refinements in the selection of patients, operative techniques and postoperative care. Future developments in immunosuppressive therapy and ongoing research efforts into the immunobiology of Eur Respir Mon, 2003, 26, b–c. Printed in UK - all rights reserved. Copyright ERS Journals Ltd 2003 European Respiratory Monograph ISSN 1025-448x. ISBN 1-904097-29-4. b