A couple of years ago a small group of people began discus sing the possibility of running an advanced summer school in the area of polymer blends. There had been a number of recent advan ces in this field, and given the considerable interest in these new polymeric materials, we thought such a meeting would be well received both by industry and academia. We wanted it to contain a wide range of background science and technology and also up to date recent advances in the field. It became clear as the discus sion progressed that the experts in the field were scattered over the length and breadth of Europe and North America and thus the cost of bringing them together for a summer school would necessi tate a high registration fee which would deter many of the research workers we wished to attract. The NATO Advanced Study Institute programme enables a subject to be covered in depth and by giving generous funds to cover lecturers' costs ensures that a wide spectrum of research workers can attend. We decided to apply to NATO and this book contains the results of our request. The ASI was funded under the 'Double-Jump' Programme which is not a new Olympic event but a way of supporting courses on sub jects of direct industrial interest. The Institute was also backed by donations from several companies and approximately half those attending were from industrial organisations.