`QCD precision for the LHC.'

Abstract: I will motivate the use of next-to-leading order (NLO) QCD
calculations for describing LHC data, and present the technique of
D-dimensional generalised unitarity which can be used to obtain the one-loop
virtual amplitudes - the bottleneck of these computations. I will also
illustrate the matching of NLO calculations to a parton shower using the
POWHEG technique.