“Galaxies are complex—many physical processes operate simultaneously, and over a huge range of scales in space and time. As a result, accurately modeling the formation and evolution of galaxies over the lifetime of the universe presents tremendous technical challenges. In this talk I will describe some of the important unanswered questions regarding galaxy formation, discuss in general terms how we simulate the formation of galaxies on a computer, and present simulations (and accompanying published results) that the Enzo collaboration has recently done on the Blue Waters supercomputer. In particular, I will focus on the transition from metal-free to metal-enriched star formation in the universe, as well as the luminosity function of the earliest generations of galaxies and how we might observe it with the upcoming James Webb Space Telescope.”