Bernard T Field and Gertrude Weiss Szilard (eds) London: MIT Press 1973 pp xxii + 737 price £7.90 Leo Szilard, perhaps the most intelligent man of our time, was born 1898 in Budapest, studied in Berlin, went to England in 1933 and later went to live in the USA. In 1928 he showed that Maxwell's demon – if its own entropy was allowed for – could not violate the second law of thermodynamics.