THE history of anthracene is long and vivid. Discovered amongst the products of coal-tar distillation in 1832, the hydrocarbon played a modest and somewhat commonplace part in the development of structural theory, suddenly blossoming into prominence in 1868, when it was found that alizarin, the twin monarch with indigo of natural colouring matters, is a dihydroxy: anthraquinone. The persistent and active investigation of anthracene derivatives consequent on this revelation had scarcely slackened in 1901, when Bohn discovered the remarkable condensation undergone by β-aminoanthraquinone, leading to indanthrene and flavanthrene, vat-dyes superior in fastness to indigo itself. During the subsequent period notable additions to the series have been made in the direction of complex benzanthrones—for example, violanthrene, a non-nitrogenous vat-dye represented as an oxygenated agglpmeration of nine benzenoid nuclei. Thus anthracene, now approaching its centenary still provides abundant material for scientific investigation and practical application. Anthracene and Anthraquinone. By E. de B. Barnett. Pp. xi + 436. (London: Bailliere, Tindall, and Cox, 1921.) 27s. 6d.