REVIEW SYMPOSIA What is This Thing Called Philosophy of Science?* Alan Chalmers, What is This Thing Called Science? Third edition. Milton Keynes: Open University Press; and St Lucia: University of Queensland Press, 1999. Pp. xxii + 266. A$19.95 PB. By John Worrall A lan Chalmers' book has been the best introduction to philosophy of science since it appeared in 1976. It remains so in 1999 courtesy of this newly published third edition. Translated into fifteen languages, the book has been a major force worldwide for straight thinking about science, q21e book, reflecting its author's own intellectual biography, is especially valuable as a way of introducing graduates in science to its philosophy. Drawing liberally on examples from the history of science, it reveals the central philosophical and methodological issues, not as dry, 'merely academic' puzzles, but as exactly the things that a reflective prac- titioner ought to worry about. Chalmers writes in a clear, direct, entirely pretension-free style, taking--unusually for an introductory account--a clear stand on virtually every issue he raises, and never being afraid to say that he finds the motivation for some of the opposing positions incom- prehensible. While some will object to this feature, the book, in my view, gains from its directness and vigour more than it loses from any lack of evenhandedness. The third edition contains a somewhat reworked version of the material from earlier editions on observation and experiment, induction, falsifica- tion, Kuhn, Lakatos and Feyerabend. A substantially reworked version of the second edition material on "unrepresentative realism" now becomes an extended account of the ongoing realism/anti-realism debate (Chapter 15). The concession to Feyerabend--made slightly mutedly in edition two-- that there is no single universal method for science is now highlighted and * The editor is very grateful to Peter Ansty for organising this excellent symposium. O AAI-IPSSS, 2000. Published by Blackwell Publishers, 108 Cowley Road, Oxford OX4 1JF, and 350 Main Street, Malden MA 02148, USA