ESDU 90008 discusses the flow phenomena that occur in steady high subsonic flow over aerofoils and wings@ and the prediction of the initial stages of shock-induced separation. The development of regions of supersonic flow on an aerofoil is first considered@ at constant angle of attack as Mach number increases and at constant Mach number as angle of attack increases. The influence of various features of the flow@ illustrated by visualisation photographs@ on the aerofoil aerodynamic characteristics is shown graphically. The interaction in attached flow of the shock with a turbulent boundary layer is considered and a correlation shows the effect of the upstream boundary layer conditions on the length of the interaction region. Shock-induced separation is then discussed@ also illustrated with graphs of the Mach number contours in the vicinity of the shock and corresponding flow visualisation pictures@ and the types of separation met are explained. A broad criterion for separation is suggested and a correlation of separation bubble length in terms of the upstream boundary layer parameters is included. A correlation of conditions for flow breakdown is also given. There is a brief discussion of the occurrence of transonic conditions on high lift devices@ where supersonic flow can exist at freestream Mach numbers as low as 0.2. Finally@ three-dimensional effects are considered@ initially in terms of the infinite yawed wing@ and then in terms of the tip effects introduced with finite aspect ratio.