The X. European Symposium on Calcified Tissues took place in Hamburg from 16th to 21 st September 1973. The financial backing came from the Gesund heitsbehorde der Freien und Hansestadt Hamburg (President Dr. Zylmann), the Bundesministerium fur Jugend, Familie und Gesundheit, and from industry. This made it possible to carry out the scientific program, to invite several European and non-European scientists, and to organize a social program designed to establish personal contact between delegates and to make visitors acquainted with our country. In the name of the organizing committee, we herewith express our warmest appreciation of all the help given to us. Professor Bartelheimer, as the representative of the Medical Faculty and on behalf of the President of the University of Hamburg, welcomed the Parti cipants in the symposium to our city. The history of these meetings began in Oxford in 1963, with the First European Bone and Tooth Symposium, organized by H. J. J. Blackwood, B. E. C. Nordin, and Dame Janet Vaughan. The idea was to found in Europe an institution simi lar to the American Gordon Research Conferences of Bone and Tooth. After the U. K. , the host countries were Belgium, Switzerland, the Netherlands, France, Sweden, Italy, Israel and Austria. The second symposium in Liege already bore the present name.