We examine the recently proposed technique of adding boundary counterterms
to the gravitational action for spacetimes which are locally asymptotic to
anti-de Sitter spacetimes. In particular, we explicitly identify higher ord
er counrerterms, which allow us to consider spacetimes of dimensions d less
than or equal to 7. As the counterterms eliminate the need of "background
subtraction" in calculating the action, we apply this technique to study ex
amples where the appropriate background was ambiguous or unknown: topologic
al black holes, Taub-NUT-AdS and Taub-Bolt-AdS. We also identify certain ca
ses where the covariant counterterms fail to render the action finite. and
we comment on the dual field theory interpretation of this result. In some
examples, the case of a vanishing cosmological constant may be recovered in
a limit, which allows us to check results and resolve ambiguities in certa
in asymptotically flat spacetime computations in the literature. [S0556-282
1(99)07318-X].