The aim of the Rolduc Polymer Meetings is to stimulate interdisciplinary discussions between academic and industrial polymer scientists and engineers. Experts are invited to review selected topics and to initiate discussions relating to future trends and developments. The general theme of these meetings is 'Integration of Fundamental Polymer Science and Technology'. In order to serve this goal, all participants are accommodated in Rolduc Abbey, a well-preserved medieval monument in Limburg (The Netherlands) to provide an optimum atmosphere for the exchange of ideas. About 350 participants took part in the 4th Rolduc Polymer Meeting, which was held from 23 to 27 April 1989. This volume contains invited and selected contributed papers on topics such as solution properties, chemistry, emulsion polymerization, liquid crystalline polymers, structure/ morphology and blends/composites. We are fully aware of the fact that the reader will not find an integrated presentation of lectures in this volume. Unfortunately, it is impossible to put down in writing the atmosphere of this and previous meetings. However, we hope that the reader will be stimulated to present his own views in forthcoming meetings after reading these proceedings. We wish to thank all contributors to this volume. P.l.L.