BOOK REVIEWS lems for two-dimensional and axisym metric flow. He also discusses the known exact solutions and the particular solutions of the Tricomi equation. Various methods of series perturbation expansions, and the transonic similarity rules, are also applied to different types of transonic flow problems. This book, in conjunction wit•h the "Mathematical Aspects of Subsonic and Transonic Cas Dynamics," by Lipman Bel's (Johu Wi ley &: Sous, 1958), should provide anyone a complete background to the t heory of invisdd trausonic flow.