The NATO Advanced Study Institute on "Electronic Structure and Properties of Polymers" was held at the Facultes Universitaires de Namur (F.U.N.) from August 31 till September 14, 1977. We wish to express our deepest gratitude to the Scientific Affairs Division of NATO, the main sponsor of this Institute, and to the Facultes Universitaires Notre Dame de la Paix and their Board who gave us generous financial help as well as accommodation for the School. Our sincere thanks to Dr Tilo Kester from the NATO Scien?? tific Affairs Division and Prof. Roger Troisfontaines, Rector and President ~f the Facultes Notre Dame de la Paix. This volume contains the main lectures of the Institute. It is our great pleasure to thank all the lecturers for their most excellent and interesting lectures and for the clarity of their manuscripts. During the School the participants and lecturers felt that though there has been considerable progress in recent years in the methods applicable to the quantum theoretical treatment of polymers, not very many calculations of their properties have been performed. This is the reason that the title of this volume has been changed to "Quantum Theory of Polymers".