  We describe techniques that simplify the calculation of one-loop QCD
amplitudes with many external legs, which are needed for next-to-leading-order
(NLO) corrections to multi-jet processes. The constraints imposed by
perturbative unitarity, collinear singularities and a supersymmetry-inspired
organization of helicity amplitudes are particularly useful. Certain sequences
of one-loop helicity amplitudes may be obtained for an arbitrary number of
external gluons using these techniques. We also report on progress in
completing the set of one-loop helicity amplitudes required for NLO three-jet
production at hadron colliders, namely the amplitudes with two external quarks
and three gluons. (Contribution presented by L. Dixon at the workshop
``QCD'94'', Montpellier, France, July 7-13, 1994. To appear in those
proceedings.)
