THESE two delightful little books deserve a special welcome, partly because they are very good value, but mainly because their authors have spared no pains to make them readable and exhilarating as well as informative and well balanced. The path of the newcomer is made smooth by the skilful presentation of modern concepts, while the professional reader is stimulated by the original and effective methods of treatment. Geology An Introduction to Earth-History. By Prof. H. H. Read. (Home University Library of Modern Knowledge, No. 198.) Pp. viii + 248. (London: Oxford University Press, 1949.) 5s. net. Minerals and Mineral Deposits A Conspectus. By Dr. W. R. Jones and Dr. David Williams. (Home University Library of Modern Knowledge, No. 202) Pp. vii + 248. (London: Oxford University Press, 1948.) 5s. net.