The NATO - EMBO Advanced Study Institute - Lecture Course on "CHROMOSOME DAMAGE AND REPAIR" was held at God¢ysund Fjord Hotel outside Bergen, Norway. from Ms\r 27th to June 5th, 1980. This book represents the proceedings of this meeting. In addition to the for­ mal lectures, a number of short contributions presented in the dis­ cussion sessions following the lectures are also included. The papers have been divided into different groups according to topic, essentially in the same way as they were presented during the meet­ ing. The editors have m. ade' few alterations in the manuscript sub­ mitted and these were mostly confined to typing style and correc­ tion ot typographical errors. We would like to express our appreciation to all the persons who helped in making this meeting possible. Special thanks are due to Tomas Lindahl, Alan R. Lehmann and Erik Boye, who served in the advisory program committee. We would also like to thank our Danish friends and colleagues and others who provided invaluable assistance in an emergency situation. The editors are also grateful for the financial support provided by a number of organizations and institu­ tions. First and foremost of these were the NATO Scientific Affairs Division and the European Molecular Biology Organization.