Anger, Gerhard Haerendel, George P. Haskell, Carl McIlwain, Vytenis Vasy­ liunas, Martin Walt, and James Warwick who served as session chairmen during the School and contributed greatly to its success by skillfully directing the discussion period in a stimulating manner after each lecture. Many persons contributed to the success of the School. Drs C. D. Anger, Carl-Gunne Falthammar, Gerhard Haerendel, George P. Haskell, Carl McIlwain, David Nunn, Willi Riedler, Finn S¢raas, Vytenis M. Vasyliunas, Martin Walt, and James Warwick were especially helpful in preparing the technical program. Dr Willi Riedler assisted in ar­ ranging for the facilities in Graz. Drs Gerhard Kremser and Martin Friedrich were most helpful with many aspects of the local arrangements in Graz. The assistant editor, Mrs Diana R. McCormac, checked the manuscripts and proofs, and worked hard to achieve a uniform style in this book.