  The production of a Higgs boson in association with a pair of t-tbar quarks
will play a very important role at both hadron and lepton colliders. We review
the status of theoretical predictions and their relevance to Higgs boson
studies, with particular emphasis on the recently calculated NLO QCD
corrections to the inclusive cross section for p-pbar,pp -> t-tbar-h. We
conclude by briefly discussing the case of exclusive b-bbar-h production and
the potential of this process in revealing signals of new physics beyond the
Standard Model.
