Jan Tinbergen presented the first macroeconometric model of the Dutch economy to a meeting in The Hague in October 1936. Since that time econometric models of national economies have developed enormously and proliferated worldwide, thanks to improvements in economic data, progress in economic theory and econometric methods, a series of revolutions in computing, and the demonstrated usefulness of the end product.This two volume set contains a selection of the key contributions to this development process, which continues to this day. The editor's introduction offers a personal commentary on each article, together with extensive references to related literature.