What did we learn about the Milky Way during the last decade,
and what shall we learn using Gaia and LSST?
Željko Ivezić
University of Washington, MTA CSFK


Studies of stellar populations, understood to mean collections of stars with common spatial, kinematic, chemical, and/or age distributions, have been reinvigorated during the last decade by the advent of large-area sky surveys such as SDSS, 2MASS, RAVE, and others. These data, together with theoretical and modeling advances, are revolutionizing our understanding of the nature of the Milky Way, and galaxy formation and evolution in general. These recent developments have made it clear that the Milky Way is a complex and dynamic structure, one that is still being shaped by the merging of neighboring smaller galaxies. I will review the progress over the last decade, and will briefly discuss new breakthroughs expected from Gaia and LSST surveys, which will improve measurement precision manyfold, and comprise billions of individual stars.