In this paper are reviewed some recent progress on the understanding and simulation of aluminum alloy age hardening. The main phenomena governing the formation of precipitate microstructures in aluminum alloys are presented; they provide a qualitative understanding of the relationship between alloy chemistry, processing and final precipitate microstructure at the nanoscale. In a second part, we describe how modeling approaches are capable of predicting these microstructures, from simple models to more advanced ones. A particular emphasis is put on the limits of these models and the strategies that are being developed to overcome them. In a third part, the mechanisms for precipitation strengthening will be discussed, as well as the models available to quantify this strengthening. Finally, in the last part, we will give some general prospects for the main developing areas of research.