The Sulfate-reducing Bacteria, J. R. Postgate. Cambridge University Press, London, UK, 1979. With 20 figures, 4 tables, viii + 151 p. $29.50 Petroleum Formation and Occurrence: A New Approach to Oil and Gas Exploration, B. P. Tissot and D. H. Welte. Springer-Verlag, Berlin-Heidelberg-New York, 1978. With 243 figures, xviii + 538 p. $39.50