  Starting from a rewiev of DGLAP and BFKL evolution equations for small-x
processes, a sistematic study is performed in order to understand the limits of
both the formulations and to improve them in a unique framework, which aims to
cover the whole range of applicability of perturbative QCD and which describes
the transition mechanism from perturbative to non-perturbative physics in the
region where unitarity contributions are expected not to be important.
