This volume contains the Proceedings of the International Workshop on the Design of Power Sonic and Ultrasonic Transducers, which was held in the Maison de l'Entreprise et des Technologies Nouvelles, Marcq en Baroeul, near Lille, France, on May 26 and 27, 1987. The main objective of this Workshop was to discuss all aspects of high power problems in the design of electroacoustic transducers and to stimulate an exchange of knowledge and experience between researchers and industrial ists involved in this multidisciplinary field. The scientific program included 13 invited contributions, and there were 80 participants from England, France, Italy, Spain, Sweden and the United States. The editors wish to thank the authors and attendees for their active par ticipation, and they hope that these Proceedings will allow readers to share in the stimulating atmosphere of the sessions. They also wish to thank eve ryone who undertook simultaneous translation, clerical work, typing of the Proceedings, production of the illustrations, or any other of the numerous tasks connected with this venture. Special mention has to be made of Mrs. E. Litton (ISEN, Lille) for her constant and kind help from the beginning of the project to the very end of the editing, Dr. R. Bossut (ISEN, Lille) for his efficient proofreading, and Dr. H.U. Daniel (Springer-Verlag) for his interest in these Proceedings as well as his kind and efficient support.