Heavy quark bound states are ideal probes of the medium formed in heavy ion collisions, and reduced yield, i.e., suppression, of these states relative to proton-proton collisions has long been theorized to signal the formation of a deconfined medium. They are formed early in the collision, are expected to dissociate in a deconfined medium and their di-lepton decay mode gives a clear experimental signature. A first-principles description of this evolution is nonetheless challenging: the states are quantum mechanical, out of equilibrium and interacting with a strongly-coupled, non-Abelian medium. In this talk, I will discuss the use of modern effective field theory methods and the formalism of open quantum systems to systematically derive a QCD master equation describing this in-medium, out-of-equilibrium evolution, discuss methods of solution and present phenomenological results