Stellar cluster research is in a dynamic state. IAU Symposium 351 (also chosen as MODEST-19, within the 'Modelling and Observing DEnse STellar systems' meeting series) is a compilation of the research presented at the Symposium. It contains highlights of the latest research taking place in many areas, including the formation of stellar clusters at high redshifts, multiple stellar populations within stellar clusters, the dynamical evolution of stellar clusters, and the production of exotic objects such as black holes within stellar clusters. This volume also includes articles on the build up of larger galaxies from smaller galaxies and stellar clusters, and discussions of the latest data from large surveys and from the Gaia satellite. Looking at both the local and the high-redshift universe allows links to be established between the clusters we see today and their progenitors. IAU S351 is an ideal entry point for astronomers new to this research field.