As Hubble and other Great Observatories peer further back into the origins of our universe, it seems we find ourselves commensurately further away from a full understanding for the origin and evolution of galaxies. The largest galaxies that we can see to the furthest distances are particularly puzzling, showing abundances and colors that present challenges for current theories of galaxy formation. I will describe recent progress from cosmological hydrodynamic simulations towards unraveling some of these puzzles. While simulations suggest a physical mechanism for the "downsizing" of galaxies, i.e., the reduction in the characteristic mass of actively star forming objects, this mechanism cannot yet explain the strength of downsizing seen in the real universe. I will then go on to describe work towards understanding the progenitors of massive galaxies as observed at z~4 by the GOODS legacy project, and present preliminary comparisons and predictions that will help us constrain the early evolution of massive systems.