Final Activity Report Summary - HQPRECISION (Precision study of heavy quark production at high energy colliders) The upcoming LHC collider physics programme will provide a wealth of precision data on a multitude of different scattering reactions. To interpret these data, a precise theoretical understanding of the underlying reactions is mandatory. Such precision calculations require the determination of scattering amplitudes in quantum field theory, which can only be accomplished in the form of a perturbation theory expansion. Already at the second order in perturbation theory, the resulting expressions turn out to be highly complex, often preventing a direct evaluation.In the project carried out here, a variety of new methods for the computation of perturbative corrections to scattering amplitudes were developed and applied. Most prominently, very important contributions were made to the unitarity-cut method, which allows the systematic reconstruction of complicated scattering amplitudes in terms of much simpler ingredients. This method was applied to obtain very compact expressions for previously unknown multi-photon and multi-gluon amplitudes, relevant for collider physics studies.