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Chirality expressed at the macromolecular level through a stereochemically biased polymerization constitutes asymmetric polymerization. An achiral or prochiral monomer is converted into a polymer that is optically active because of main-chain stereocenters, a preferred helical screw sense, or both. The bias may originate in a chiral initiator or catalyst, a chiral field such as a liquid-crystalline medium, or a chiral auxiliary attached to the monomer. Helical polyacetylene formed in a chiral liquid-crystal field is a canonical illustration of field-induced asymmetric polymerization ^[1]. In the polymerization of 1,2-diisocyanobenzenes, a screw-sense-determining end group dictates the helical sense of the growing poly(quinoxaline-2,3-diyl) chain ^[2]. Asymmetric polymerization-induced crystallization-driven self-assembly of poly(aryl isocyanide) block copolymers likewise couples helical chain growth to hierarchical assembly ^[3]. The term is reserved for polymerization that creates macromolecular asymmetry; it is not synonymous with polymerization of an already enantiopure monomer that merely preserves point chirality, nor with racemic polymerization that yields internally compensated stereosequences.