This issue of the ICMI Bulletin which you are now reading (on paper or electronically) marks the fiftieth appearance of this vehicle of communication launched in 1972 by the Executive Committee of ICMI in order to facilitate the dissemination of information concerning activities of the Commission and other matters of interest to mathematics educators around the world. The ICMI Bulletin was at times published somewhat erratically, but two issues have appeared each year since 1984. While it does contain formal information about ICMI (vg statutory annual or quadrennial reports), the main purpose of the Bulletin is to provide easily accessible information related to various aspects of the life of the Commission (announcements of activities, calls for contributions, information about affiliated Study Groups, etc.) as well as to general mathematics education issues as seen from an international perspective. Hence the collection of the past issues of the ICMI Bulletin can be seen as a unique source of information on the history of the Commission itself and on aspects of the evolution of international trends in mathematics education. (The tables of contents of the first 45 issues of the ICMI Bulletin, published between 1972 and 1998, has been given in issues Nos. 46 and 47, June and December 1999.) Complementary information about ICMI can be found in L'Enseignement mathématique, the official organ of the Commission.
It was felt appropriate to underline the publication of this fiftieth issue of the ICMI Bulletin in some specific way. The mathematics education community is extremely fortunate that four Presidents of ICMI, the current President and three of his four most recent predecessors, are present with us to share their reminiscences of their term as President and their views on current trends and issues in mathematics education and the role the Commission could or should play. I am grateful to Presidents Shokichi Iyanaga (1975-1978), Jean-Pierre Kahane (1983-1990), Miguel de Guzmán (1991-1998) and Hyman Bass, the current President, for having accepted my invitation to prepare a text for this issue of the ICMI Bulletin. I especially wish to express my gratitude, admiration and best wishes to President Iyanaga, now 95 years of age, who showed throughout the contacts I recently had with him an extraordinary sense of vivacity and wit.Bernard R. Hodgson