New Trends in Genetic Risk Assessment is based on the Fifth International Round Table of the Rhône-Poulenc Santé Foundation, held in Nice 1987. The conference was an attempt to review the latest theories and mechanisms stipulated for the various aspects of genotoxicity; it was above all an open forum to discuss the new trends, the new tests, and the new battery of tests for assessing the genetic risk of chemicals and especially drugs. This volume is actually not a proceedings of the meeting but a monograph specially edited to report the reviews which were presented and the discussions which took place; it was designed to provide a better understanding of the knowledge obtained in the most recent years and to help in the practical choice of approaches or tests for the prediction of the various forms of genotoxicity. The main subjects of this review concern molecular analysis of mutagenesis, detection of DNA damage, gene mutation, clastogenesis, aneuploidy, and germ cells. Each theme is preceded by a short overview summarizing the state of the art and the contributions of each author. Finally, special attention was given to the personal views of some leading toxicologists as to the battery of tests presently available or recommended.