VERY little of a vast literature on rocket research has yet been published in book form or as papers in scientific journals. This is perhaps inevitable, since the development of the modern rocket has been due to the requirements of the War, and the numerous existing reports and papers, in many fields of scientific and technical endeavour, still carry a security ban. In recent years a book has been published, "The Mathematical Theory of Rocket Flight", by Rosser, Newton and Gross (for review, see Nature, 161, 3 ; 1948), which represents an American contribution and which deals with the ballistics of unrotated rockets. A paper by Dr. R. A. Rankin is the first extensive presentation of the wider theory including rotated rockets, and is by far the most important British paper so far published. The Mathematical Theory of the Motion of Rotated and Unrotated Rockets By R. A. Rankin. (Phylosophical Transactions of the Royal Society of London, Series A: Mathematical and Physical Science. No. 837, Vol. 241.) Pp. 457–585. (London: Cambridge University Press, 1949) 30s.