Expanded version reprinted in The Energy Journal , Vol. 5, No. 3, July 1984, pp. ll-25; further expanded version reprinted in J. W. Kendrick (ed.), International Comparisons of Productivity and Causes of the Slowdown , Cambridge, Ballinger, 1984, pp. 279-323; reprinted in Italian as "Il Ruolo dell'Energia Nella Crescita della Produttivita," Energia , Vol. 5, No. 4, Dicembre 1984, pp. 50-55; reprinted in S. H. Schurr and S. Sonenblum (eds.), Electricity Use, Productive Efficiency and Economic Growth , 1986, Palo Alto, Electric Power Research Institute, pp. 43-92. Econometrics 1, ch. 14, pp. 403-456.