I will review the processes of making the elements in various astrophysical environments, emphasizing the role of fundamental physics and observational evidence. I then discuss how to understand chemical evolution from both the ab initio and the data-driven approaches, contrasting the respective central issues. To illustrate the latter approach, I show how the average production patterns of Fe, Sr, Ba, and Eu by core-collapse supernovae and neutron star mergers can be inferred from the data on old stars in the Milky Way.