My research is focused on understanding the structure and formation of galaxies, in particular the Milky Way. I use data from large surveys to investigate the distribution of stars in the Milky Way and how this distribution depends on the age and chemical composition of stars, which allows me to identify the basic processes that govern the formation and evolution of the Milky Way and disk galaxies like it. I am also interested in using the observed kinematics of stars to infer the distribution of mass—dark matter in particular—in our Galaxy. I am an active member of the APOGEE survey, which uses high-resolution, high signal-to-noise infrared spectroscopy to investigate the structure of the bulge and disk regions of the Milky Way, as well as many other topics in stellar and galactic astrophysics.