MANY branches of science have had their seeds planted some forty years ago and in the intervening period have germinated, grown and flourished to such an extent that massive trees now stand on previously bare earth. The physics and chemistry of surfaces is in this category, and the historian follows this growth first by means of a monograph and then with a text-book in which edition follows edition. Prof. N. K. Adam is universally recognized as one of the historians of this subject, and we welcome his third edition of his well-known text-book. The Physics and Chemistry of Surfaces By Prof. Neil Kensington Adam. Third edition. Pp. xii + 436. (London: Oxford University Press, 1941.) 22s. 6d. net.