Well-defined homopolymers of styrene, 2-vinyl pyridine and ethylene oxide and AB block copolymers of polystyrene and poly(ethylene oxide) with narrow molecular weight distributions have been prepared by anionic polymerisation techniques. These polymerisations required conditions of rigorous purity, and high vacuum and inert gas atmosphere methods have been used. The preferred anionic initiator for ethylene oxide and 2-vinyl pyridine polymerisations was cumyl potassium which was prepared by a vacuum line procedure. Polymers were characterised by gel permeation chromatography, infra-red spectroscopy, membrane osmometry and solution viscometry to determine molecular weights, polydispersity ratios and copolymer compositions.