Hard processes such as DIS, electron-positron annihilation, Drell-Yan pair production as well as jets in p-p collisions are well described by pQCD based on a factorization approach. We show that a simple extension of this approach, based on the study of length enhanced power corrections, may be used to describe a wide range of phenomena in the case of jet modification in dense extended matter. This includes both cold nuclear matter and hot deconfined quark gluon plasmas. After an introduction to the underlying assumptions and a derivation of the basic jet modification formulae, we will apply this formalism to understand different phenomena such as single and double inclusive suppression in DIS on a large nucleus and in a heavy-ion collision. Following a discussion of the various transport coefficients, we will also discuss the calculation of heavy flavor energy loss and energy deposition. We will conclude with an overview of the calculations that need to be done to place this analysis on a more rigorous footing and provide estimations of the error.