The series of international symposia on Enzootic Bovine Leukosis (EBL) sponsored by the Commission of the European Communities, began in 1975 in Copenhagen. This latest symposium, the third, was held in Bologna, 5-7 November 1980. If we compare the two proceedings it is quite evident how much progress has been achieved in EBL research during these few years. Whereas in 1975 there were still discussions on the character­ isation and importance of the various identified antigens and the anti­ bodies against them, we now have evidence of base sequence variations of the bovine leukosis provirus derived from cattle in different conti­ nents, due to the world-wide cooperation on the subject. Disease control was still largely based on haematology, whereas now some countries are completely free, or on the verge of becoming completely free, of the disease following the introduction of serological methods of diagnosis. EBL research appears to me to be an excellent example of the pro­ duction of new fundamental research and its transfer to the applied disciplines of veterinary sciences. I must emphasise that this progress would not have been achieved if the CEC had not sponsored a number of projects and the meetings. I should like to thank the CEC for this continued sponsorship, Prof. Dr. Gentile, whose invaluable assistance helped to ensure the quality of the symposium and Janssen Services for their work in preparing the proceedings and assistance with the editing of the papers and dis­ cussion.