  I present a brief review of the stellar population properties of massive
galaxies, focusing on early-type galaxies in particular, with emphasis on
recent results from the ATLAS3D Survey. I discuss the occurrence of young
stellar ages, cold gas, and ongoing star formation in early-type galaxies, the
presence of which gives important clues to the evolutionary path of these
galaxies. Consideration of empirical star formation histories gives a
meaningful picture of galaxy stellar population properties, and allows accurate
comparison of mass estimates from populations and dynamics. This has recently
provided strong evidence of a non-universal IMF, as supported by other recent
evidences. Spatially-resolved studies of stellar populations are also crucial
to connect distinct components within galaxies to spatial structures seen in
other wavelengths or parameters. Stellar populations in the faint outer
envelopes of early-type galaxies are a formidable frontier for observers, but
promise to put constraints on the ratio of accreted stellar mass versus that
formed 'in situ' - a key feature of recent galaxy formation models. Galaxy
environment appears to play a key role in controlling the stellar population
properties of low mass galaxies. Simulations remind us, however, that current
day galaxies are the product of a complex assembly and environment history,
which gives rise to the trends we see. This has strong implications for our
interpretation of environmental trends.
