THIS book does a great service by collecting together much scattered information on a fascinating and rapidly developing subject, contributions to which have appeared in a great many different journals. Discussion of liquids inevitably leads on to such topics as fusion and evaporation, the theory of solutions, the properties of polymers and rubber-like substances, and so on. Certain of these topics are dealt with at considerable length, others rather sketchily, and it is regrettable that no attempt has been made to link up the statistical theory of turbulence with the molecular theory of liquids. As is inevitable in so vast a subject, some of the matter is already out of date, and it is only right to mention that the book was written in Moscow in 1942, and has suffered delay in publication. In spite of these shortcomings, the book fills a very obvious gap, and cannot fail to be of permanent value to a serious student of any of these subjects. In spite of the War, the book is printed on very nice paper, and the high standard of craftsmanship that one instinctively associates with this series of monographs has been well maintained. The references are given in footnotes, which is far more convenient than grouping them at the end of the chapters, but one would welcome a complete bibliography at the end of the book, or else a subject index. Another improvement that could easily be made in a new edition is the addition of a list of symbols. Kinetic Theory of Liquids By J. Frenkel. (International Series of Monographs on Physics.) Pp. xi + 488. (Oxford: Clarendon Press; London: Oxford University Press, 1946.) 40s. net.