therapies, as well as progress in basic research on regenerative therapies that are needed to improve outcome of patients with irreversible lung damage. Despite this enormous progress, important challenges remain that have to be solved in order to deliver disease-modifying treatment, ideally in all patients. These challenges range from the development of drugs that rescue a broader spectrum of CFTR mutations in the laboratory, including the most common mutation Phe508del, all the way to the training of a larger number of CF specialists, who are urgently needed in clinics for competent care of the rapidly growing population of patients with CF as they grow older. This issue of the ERS Monograph provides an update on all aspects of CF lung disease, from infancy to adulthood, including current pathogenetic concepts of mucus plugging, chronic airway inflammation and polymicrobial infection, improvements in early diagnosis and monitoring, mutation-specific and other therapeutic approaches, and important issues related to further improvement of patient care. In state-of-the-art chapters, international experts in the field highlight important recent developments and discuss the next steps that will be required for further improvement of life expectancy and quality of life of patients with CF. As editors, it was a great pleasure to assemble this Monograph in the year of the 25th anniversary of the discovery of CFTR, and we trust that it will be a useful reference for basic and clinical scientists, and all members of the CF team. xiv