The new edition of Prof. Rinne's book is considerably larger than the first edition, and presents an altogether wider outlook on the fine structure of matter as exhibited in crystals. The whole work is enriched by an originality of treatment which renders it eminently readable and suggestive. Moreover, the excellent portraits of von Groth, Hauy, Schoenflies, Fedorov, Tschermak, von Laue, Debye, Scherrer, Sir William Bragg, and W. L. Bragg give it an altogether special interest. A reproduction of Albrecht Durer's picture “Melancholie” is also given, in which the representation of a huge crystal occupies a prominent place, the inference being that Diirer was oppressed by the idea of the hopelessness of man's ever rising to the comprehension and explanation of a natural phenomenon so wonderful and remarkable as that of crystallisation. If Diirer lived to-day, however, how different would be his picture ! Its title might well be “Hope,” or even “Achievement,” rather than “Melancholie.” It is this extraordinary success of recent crystallo-graphic and physical research, and particularly that brought about by the use of X-rays in elucidating the arrangement of the chemical atoms in crystals, that forms the main theme of Prof. Rinne's book, and he regards the whole achievement in its more fundamental aspect, as having revealed the true nature of the fine-structure of solid matter. The book is full of illustrations and diagrams of an original character, including many of the X-radiograms of crystals due to Prof. Rinne's own industry. It is a book of very special merit, and one of the most suggestive and far-seeing that have appeared since the inauguration of these fruitful new methods of research. Das feinbauliche Wesen der Materie nach dem Vorbilde der Kristalle. Von Prof. Dr. Friedrich Rinne. 2 und 3 erweiterte Auflage. Pp. viii + 168. (Berlin: Gebrüder Borntraeger, 1922.) 10s. 4d.