THESE two books deal essentially with the same problem, that of forecasting tomorrow's weather, but they will appeal to different classes of readers. According to the publisher's note on the cover, Major Lester's book combines the functions of supplying the serious student of meteorology with an introduction to the deeper study of the subject and of supplying the amateur forecaster with an infallible guide. Some experience of trying to forecast to-morrow's weather has, however, convinced the present reviewer that no infallible guide to forecasting can be provided, either for the professional or the amateur meteorologist. Sir Napier Shaw has produced a third edition of his “Forecasting Weather”, which appears to be intended for the scientific student of the subject. It is, perhaps, not unfair to say that while Major Lester has described the observed phenomena and their associations, Sir Napier Shaw has endeavoured to describe and to explain the phenomena in which he is interested. (1) Weather Prediction By Major R. M. Lester. Pp. 256. (London: Hutchinson's Scientific and Technical Publications, 1940.) 10s. 6d. net. (2) Forecasting Weather By Sir Napier Shaw. Third edition, with a Supplementary Note on Sixteen Years' Progress in Forecasting Weather, by R. G. K. Lempfert. Pp. xliii + 644. (London: Constable and Co., Ltd., 1940.) 42s. net.