We review recent developments in the QCD description of jet production and modification in reactions with heavy nuclei at relativistic energies. Our goal is to formulate a perturbative expansion in the presence of nuclear matter that allows to system
atically improve the accuracy of the theoretical predictions. As an example, we present calculations of inclusive jet cross sections at RHIC, Z0/gamma*-tagged jet cross sections at the LHC, and jet shapes that include both next-to-leading order perturbative effects and the effects of the nuclear medium.
