  Let R be a polynomial ring over k(u), where k is a field k and u is a finite
family or inderterminates. The paper introduces the specialization of an
arbitrary finitely generated R-module by the substitution of u to elements of
k. This definition does not depend on the presentation of the given module and
preserves basic properties and operations on modules (e.g. annihilator,
dimension, Ext and Tor) for almost all specializations.
