New three-dimensional measurements of the positions and velocities of stars, in particular from the Gaia observatory, have provided unprecedented information on the dynamics of the Milky Way and nearby dwarf galaxies. I will discuss how these observations have impacted our understanding of hierarchical structure formation in the Universe, the Milky Way, and the Local Group of galaxies. I will discuss what we can expect to learn from future astrometric data and surveys, including connections to the nature of dark matter.
