[en] Since the pioneer work of the United States Department of Agriculture in the application of radiation and radioisotopes in the control of insect pests to cattle, many countries and organizations have pursued the advantages which might be gained in this field. Two years ago the IAEA organized the first international symposium in Bombay to study this problem, since when a considerable amount of basic research on the application of nuclear science in entomology and insect pest control has been undertaken. The potential gain of these studies, which would be in the form of an increased output of better food, is obvious to all Governments; hence the extensive international interest in the subject of this present Symposium, which was attended by 100 participants from 26 countries and 5 international organizations. The proceedings consist of 37 papers presented by experts from 10 countries, together with a record of the discussions, and cover the use of radioisotopes in the study of the ecology of insects, such as their dispersal, migration and life-cycle. The application of radioisotopes to insecticides covers such subjects as labelling, application, uptake, translocation, metabolism, mode of action, and the determination' of residues in plants and animals. The present position on the effects of radiation on insects is dealt with, including mutation, sterilization and the use of the sterile-male technique for the control and eradication of insect pests, and the need is emphasized for integration of chemical, biological, radiation and other methods of insect control. The emphasis of this Symposium has been mainly on aspects of crop protection and it is hoped that the next symposium will also deal with aspects of livestock protection.