Non-perturbative renormalization in lattice QCD

In this talk I will discuss a number of approaches designed to deal with the problem of setting up a fully non-perturbative renormalization procedure in lattice QCD. Methods based on Ward-Takahashi identities on hadronic states, on imposing chiral selection rules on amplitudes with external quark/gluon legs, on the use of the Schr"{o}dinger functional and on heating and cooling'' Monte Carlo steps are reviewed. I conclude with some remarks on the possibility of defining next order terms (higher twists, condensates", …) in short distance expansions.