Making action-angle disc models for Gaia
  A brief review of recent work. I describe dynamical modelling of the Milky
Way using action-angle coordinates. I explain what action-angle coordinates
are, and what progress has been made in the past few years to ensuring they can
be used in reasonably realistic Galactic potentials. I then describe recent
modelling efforts, and progress they have made in constraining the potential of
the Milky Way and the local dark matter density.
