Block polymers represent another milestone in the preparation of polymers of controlled structure. Catalysts and polymerization methods that allowed the preparation of polymers in which the stereo- and geometric isomerism of the monomer units could be con trolled have indeed been among the major developments in polymer science during the last decade. The synthesis of block polymers, in which the sequence length of the comonomer units can be con trolled, portends equally important developments in the science and technology of polymers. The papers collected in this volume cover primarily the...