We derive the renormalization group equations for a generic nonrenormalizable
theory. We show that the equations allow one to derive the structure of the
leading divergences at any loop order in terms of one-loop diagrams only. In
chiral perturbation theory, e.g., this means that one can obtain the series of
leading chiral logs by calculating only one loop diagrams. We discuss also the
renormalization group equations for the subleading divergences, and the crucial
role of counterterms that vanish at the equations of motion. Finally, we show
that the renormalization group equations obtained here apply equally well also
to renormalizable theories.Comment: 40 pages, 4 figures, plain Late