  We derive an effective field theory describing a pair of gravitationally
interacting point particles in an expansion in their mass ratio, also known as
the self-force (SF) expansion. The 0SF dynamics are trivially obtained to all
orders in Newton's constant by the geodesic motion of the light body in a
Schwarzschild background encoding the gravitational field of the heavy body.
The corrections at 1SF and higher are generated by perturbations about this
configuration -- that is, the geodesic deviation of the light body and the
fluctuation graviton -- but crucially supplemented by an operator describing
the recoil of the heavy body as it interacts with the smaller companion. Using
this formalism we compute new results at third post-Minkowskian order for the
conservative dynamics of a system of gravitationally interacting massive
particles coupled to a set of additional scalar and vector fields.
