The major research interest of the past 10 years has been microbial biofilms in relation to cell–cell interactions and developmental processes. The knowledge obtained in the course of this work is now being further developed in connection with detailed studies of microbial adaptation and evolution in cases of chronic infection. These current research activities are based on the assumption that fundamental studies of bacteria physiology and ecology are essential to understand and eventually interfere with such microbial infections. The investigations employ several methods providing global information about the cells’ genomes and functional genomics. In particular, specific clones of bacteria infecting the airways of people with cystic fibrosis are being studied. In connection with these studies, the evolution of antibiotic resistance is an important topic, and the current focus point is the resistance mechanisms involved in tolerance to antimicrobial peptides. The development of various types of laboratory model systems for simulating human infections in vitro has been added to the research programme.