In June 1983 the Astronomical Institute of the State University of Groningen, founded by Kapteyn about 100 years ago, celebrated its one-hundredth anniversary. At the suggestion of its Chairman, R.J. Allen, the Kapteyn Institute invited the International Astronomical Union to mark the centenary by holding a Symposium on "The Milky Way Galaxy". The purpose of the Symposium was to review recent progress in the study of our Galaxy, to define current...