  A general strategy to solve the non-perturbative renormalization problem in
lattice QCD, using finite-size techniques and numerical simulations, is
described. As an illustration we discuss the computation of the axial current
normalization constant, the running coupling at zero quark masses and the scale
evolution of the renormalized axial density. The non-perturbative calculation
of O(a) correction terms (as they appear in Symanzik's improvement programme)
is another important field of application.
