In the academic year 1977-1978 Tilburg University celebrated its fiftieth anniversary. The commemoration involved specific scientific activities. The theme of 'Innovation', broadly de fined as 'developments in sciences and society', offered the scientific framework in which these activities took olace. The present volume is one of the results. It consists of the texts of a series of lectures held at the Department of Eco nomics of Tilburg University. The Department's Colloquium Committee, set up to organize discussions on current research, arranged the lectures. On this occasion, the...