Catalysis continues to play a vital role in polymerization of such olefins as ethylene and propylene. A voluminous patent and scientific literature describing transition metal catalysts for olefin polymerization has emerged since the original discoveries by Ziegler, Natta, and other workers [1–6], Significant progress in polymerization catalysis has been made in the last 15 years, particularly with the development of methods to increase the efficiency of transition metal catalysts in olefin polymerization. Success in this area has provided the basis of simplified, less costly plant operations which do not require removal of residual catalyst from the polymer [3–9].