Metallocene/aluminoxane catalysts are among the most important recent discoveries in the field of catalytic polymerization of olefins. Not only their high activities, but also the fact that they permit the synthesis of polymers with superior blends of properties are remarkable both from academic and industrial points of view. This paper will review the major scientific publications and patents regarding metallocene catalysts for the polymerization of olefins and propose a tentative model for catalyst behaviour based on the application of the Stockmayer Bivariate Distribution.