Stars on the asymptotic giant branch (AGB stars) play an important role due to their high luminosity and production of heavy elements and cosmic dust. They are prime laboratories for studying situations where different physical and chemical processes work simultaneously, on different time scales. IAU Symposium 343 builds a bridge between research on AGB stars themselves and their applications to the modelling of stellar populations and the chemical evolution of galaxies. Our understanding of these complex stars is given using insights into many aspects of physics and chemistry, while very high-angular resolution observations of AGB stars and their surroundings provide strong constraints on stellar theory and how they lose matter through strong stellar winds. This volume also highlights the difficulties in estimating the importance of AGB stars for various aspects of galaxies. Current developments and challenges of these complex objects are discussed for a broad, interdisciplinary audience of astronomers.