Subscripts B A computer code based on the method of characteristics is applied to the study of twoand three-dimensional chemical nonequilibrium flow over sharpand blunt-nosed bodies. Nonequilibrium flow over a wedge is used to show the approach to equilibrium flow and to demonstrate the nature of the reaction zone behind the bow shock wave. The structure and development of a blunt-body entropy layer in nonequilibrium flow is examined for a blunt cone at zero incidence. Three dimensional computations for the Space Shuttle body at 30 deg angle of attack are presented. A nondimensional scaling parameter, the Damkohler number (the ratio of flow time to chemical reaction time) is calculated and its significance discussed. .