This survey of James M. Buchanan's contributions to economics is divided into eig ht main categories: the influence of Knut Wicksell and the pure theory of govern ment finance; the Italian tradition and the burden of national debt; the calculu s of consent; application of the public choice approach; application to public f inance; public goods and clubs; fiscal constitutions; and the reason of rules. A bibliography of Buchanan's publications, 1949 to 1986, concludes the survey. Copyright 1987 by The editors of the Scandinavian Journal of Economics.