We review recent progress using amplitudes methods to obtain new results for the conservative
classical scattering of two massive black holes at order O(G^4). We include contributions from
both potential and radiation modes which effect the conservative dynamics through the tail effect.
We compute the 2 → 2 scattering amplitudes and extract the radial action through the amplitude-
action formula and derive the scattering angle. By matching we also obtain a Hamiltonian valid
for arbitrary scattering trajectories.