Modeling of the flux emitted by unresolved stellar populations stands as one of our most powerful tools to unveil the physics of galaxies.

With this conference, we aim at putting together the latest advances in the understanding of the stellar content in galaxies, as well as identifying the challenges for the immediate future regarding both stellar population modeling and analysis with the largest telescopes and newest simulations. This will be the ideal benchmark to celebrate the profound personal and scientific contributions that Alexandre Vazdekis has made to this topic: together with observers, theoreticians, and simulators who, like Alexandre, have devoted or will devote their lives to the study of unresolved stellar populations.