The idea of this Colloquium came during the XVIIth General Assembly of the I. A. U. at Montreal. The meeting was organized under the auspices of I. A. U. Commission 5 (Documentation and Astronomical Data). The Scientific Organizing Committee consisted of C. Jaschek (chairperson), O. Dluzhnevskaya, B. Hauck (vice chairperson), W. Heintz, P. Lantos, Th. Lederle, J. Mead~ G. Ruben, Y. Terashita, G. Wilkins. The members of this Committee are to be thanked for their devotion to the organization of what turned out to be a very successful meeting. The program was organized so as to cover most of the aspects concerning work with machine readable data. In a certain sense it is the develop ment of the subjects of I. A. U. Colloquium 35 "Compilation, critical evaluation and distribution of stellar data" held at Strasbourg in 1976. The meeting was opened by welcoming addresses delivered by Dr A. Florsch, Director of the Strasbourg Observatory, Prof. H. Curien, President of the European Science Foundation and Prof. W. Heintz, President of I. A. U. Commission 5. The sessions were devoted to the fol lowing subjects : Existing data centers, Data networks, New hardware, Recent software developments, Bibliographical services, Copyright, Editorial policies and nomenclature, Data in astronomy and Data in space astronomy. The different sessions were chaired by G. A. Pilkins, J. Mead, S. Lavrov, W. Heintz, P. Lantos, M. McCarthy, J. Delhaye and G. Westerhout. On July 9. Dr A.