matches, and bicyc1e races, and even some convivial­ ity akin to that of a c1ass reunion with members telling their stories of yesterday and visions of tomorrow. All these serious scientific disputations and the friendly exchanges would not have been possible without the major assistance from NATO and other institutions and individuals. We wish to express our deep appre­ ciation to Dr. L. v. da Cunha ofNATO Scientific Affairs Division, Dr. Tilo Kester and Mrs. Barbara Kester of the International Transfer of Science and Technology (ITST) for their active support and substantial assistance throughout the Advanced Study Institute; Mr. Charles Stockman and his staff of the Chateau de Bonas for looking after our stay there; Christi Martin and Xi-Wu Feng of Oklahoma State University, and the University of Saskatchewan generally for facilitating our work.