Abstract: Observations of the structure and dynamics of different stellar populations in the Milky Way's disk provide a unique perspective on disk formation, evolution, and dynamics. I will review our current knowledge of the chemo-orbital structure of the disk. I will then discuss new measurements of the kinematics and chemistry of intermediate-age stars over a large part of the Galactic disk from the APOGEE survey and the new insights these measurements provide about the formation and evolution of the disk.