We present an analysis of the effects of heating, suction, and compressibility on the stability characteristics of boundary-layer flows within the framework of a complete nonparallel, linear, spatial stability theory. Included in the theory are disturbances due to velocity, Pressure, temperature, density, and transport properties as well as 'variations of the fluid properties with temperature. The method of multiple scales is used to account for the nonparallelism of the mean flow and equations are derived for the evolution of the disturbance amplitude and wave number vector. / Ph. D.