The present fifth conference in this series - counting the 1956 conference in Mainz the same way as the "zeroth" symphonies of Beethoven and Bruckner - was held in conjunction with the centennial of the "Convention du Metre" which was signed May 20, 1875 in Paris, Because of this occasion, an extensive honorary committee was appointed: Honorary Committee; Chairman A. Kastler R. C. Barber(M) W. H. Johnson(M) K. Ogata(M) u. Bonse E. R. Cohen(M) Y. Sakurai A. H. Cook J. H. Sanders(M) P, Dean H. H. Staub(M) R. D, Deslattes U. Stille(M) J. V. Dunworth J, Terrien(M) V. I. Goldanskii(M) M. A. Thompson P. Grivet A. H. Wapstra(M) The members (marked M) of the Commission on Atomic Masses and Fundamental Constants of the International Union of Pure and Applied Physics belonged ex officio to this Committee, The Organizing Committee; chairman A, Horsfield H. Capptuller J . E. Faller J . L. Hall B. W. Petley B. N. Taylor was helped by the following two committees: v vi PREFACE Program Committee; chairman A. H. Wapstra c. Audoin W. H. Johnson W. Benenson R. Klapisch E. R. Cohen A. Rytz P. Giacomo J. H. Sanders Local Committee; chairman P. Grivet c. Audoin R. Klapisch N. Elnekave Y. Le Gallic s. Gerstenkorn P. Petit F. Hartmann M. 1 The Fundamental Constants and Metrology.- 2 Gamma rays.- 3 Alpha and Beta Decays.- 4 Nuclear Reactions.- 5 Mass Spectrometry.- 6 Theory of Nuclear Binding Energies.- 7 Atomic Mass Formulae.- 8 Time and Frequency Measurements and the Speed of Light.- 9 Wavelength Comparison.- 10 The Josephson Effects and 2e/h.- 11 Magnetic Moments.- 12 Miscellaneous Constants.- 13 Relativity, Time Variation of the Constants, and Philosophical Considerations.- 14 Evaluation.- 15 Conference Summary.