This book collects the Proceedings of a workshop sponsored by the European Molecular Biology Organization (EMBO) entitled "Pro­ teins Involved in DNA Replication" which was held September 19 to 23,1983 at Vitznau, near Lucerne, in Switzerland. The aim of this workshop was to review and discuss the status of our knowledge on the intricate array of enzymes and proteins that allow the replication of the DNA. Since the first discovery of a DNA polymerase in Escherichia coli by Arthur Kornberg twenty eight years ago, a great number of enzymes and other proteins were des­ cribed that are essential for this process: different DNA poly­ merases, DNA primases, DNA dependent ATPases, helicases, DNA liga­ ses, DNA topoisomerases, exo- and endonucleases, DNA binding proteins and others. They are required for the initiation of a round of synthesis at each replication origin, for the progress of the growing fork, for the disentanglement of the replication product, or for assuring the fidelity of the replication process. The number, variety and ways in which these proteins inter­ act with DNA and with each other to the achievement of replication and to the maintenance of the physiological structure of the chromo­ somes is the subject of the contributions collected in this volume. The presentations and discussions during this workshop reinforced the view that DNA replication in vivo can only be achieved through the cooperation of a high number of enzymes, proteins and other cofactors.