Turbulent flow is a most important branch of fluid dynamics yet its complexity has tended to make it one of the least understood. Empirical data have been appearing rapidly for more than twenty years but a consistent theory of turbulent flow based on the results has been lacking. The original edition of Dr Townsend’s book was the first to attempt a systematic and comprehensive discussion of all kinds of turbulent motion and to provide a reliable analysis of the processes which occur. The theory and associated concepts are applied to the description of a variety of flows: free turbulent flows such as wakes and jets, wall flows in pipes and boundary layers, flows affected by buoyancy forces such as heat plumes and the atmospheric boundary layer and flows with curved streamlines. This monograph will appeal to practitioners and researchers in engineering, meteorology, oceanography, physics and applied mathematics. This paperback edition was first issued in hard covers in 1976 as a complete revision, taking into account developments since 1955, of the first edition. It will be useful as an advanced text in applied mathematics, and the other disciplines mentioned above.