These two parts in?Elsevier?s Encyclopaedia of Organic Chemistry? take their respective volumes a stage nearer completion. In the first the literature is stated to be covered up to 1944 and the literature concerning the structure of compounds up to 1955, while in the second the coverage is up to 1946 with reference to papers on structure and configuration up to 1955. As might be expected, in view of the subjects treated, references to publications of the past decade are more abundant in the second of these parts than in the first. Naphthalenesulphonic acids and their amino and hydroxy-derivatives are, to the dyestuffs chemist, among the most important derivatives of naphthalene, and this part of Vol. 12B deals with such compounds containing one sulphonic acid group and also with azo dyes related to them. In regard to the latter, it is useful to find references to their numbers in the?Colour Index? and in?Farbenstofftabellen?, and it is also to be noted that the lists of references include not only titles of scientific periodicals but also some of the more important patent specifications and such well-known monographs as those of Fierz-David and of Venkataraman. True to the traditions of the?Encyclopaedia?, interesting information about biological properties is scattered through the part; thus, there is reference to the plant growth-promoting action of such compounds as the sulphonic acid analogue of 1-naphthylacetic acid; we read that 2-naphthol-6-sulphonic acid is only moderately toxic to body lice ; and there is a brief digest of the voluminous literature on the biological properties of congo red. A useful feature is the list of trivial names of naphthalenesulphonic acids and their derivatives. This includes also the compounds with more than one sulphonic acid group, which are not otherwise dealt with in this part. It is valuable to have so much information about the sulphonated naphthalene derivatives arranged in such compact and easily accessible form, even though much of the material is already summarized in monographs and other publications.The Supplement to Vol. 14, on steroids,?comprises the halogen and nitrogen substituted mono-hydroxylated compounds with one OH in the ring system, and all polyhydroxylated compounds, having at least one OH in the ring system, with or without halogen or nitrogen substituents?. Hence there is included the addition products of sterols with halogens and halogen acids, the nitro-, amino- and azo-derivatives of the sterols, the cestradiols, cestratriols and diols and triols of the androstane, pregnane, cholestane and ergostane series. Configurations are given so far as they are known, and the work will be an invaluable compendium to those interested in steroid chemistry. There are the usual tables of physical constants of the more important groups of compounds, references to physiological properties, usually?cestrogenic or androgenic activity, and the part is liberally supplied with editorial footnotes clearing up points of obscurity or confusion in the original literature. Both parts reach the standard of excellence of production to which users of?Elsevier?s Encyclopaedia? are now well accustomed.