  The ADM formalism for two-point-mass systems in $d$ space dimensions is
sketched. It is pointed out that the regularization ambiguities of the 3rd
post-Newtonian ADM Hamiltonian considered directly in $d=3$ space dimensions
can be cured by dimensional continuation (to complex $d$'s), which leads to a
finite and unique Hamiltonian as $d\to3$. Some so far unpublished details of
the dimensional-continuation computation of the 3rd post-Newtonian
two-point-mass ADM Hamiltonian are presented.
