THIS volume contains, among papers on a wide range of subjects, a symposium on "The New Physics and Metaphysical Materialism" in which the late Prof. Susan Stebbing, Sir James Jeans, Mr. R. B. Braithwaite and Prof. E. T. Whittaker took part (see Nature, June 19, 1943, p. 686). Prof. Stebbing in her life-time was convinced that Eddington and Jeans used their standing as scientific men to put across to the public metaphysical views which were thoroughly unsound. In her contribution to this symposium she argues that "the new physics does not imply idealism" (p. 184). If Sir James Jeans thinks it does, it is because he argues, erroneously, that because the wave-picture of the universe is essentially mental, the universe it pictures must be so also. Proceedings of the Aristotelian Society New Series, Vol. 43: Containing the Papers read before the Society during the Sixty-fourth Session, 1942–1943. Pp. xxvi + 222. (London: Harrison and Sons, Ltd., 1943.) 25s. net.