This study presents a simple means of calculating the skin friction for a flat plate with a minimum of parameter interpretation. The method employs parameters familiar to aerodynamicists, such as Reynolds number, wall temperature, and Mach number, and is based on D. E. Coles' theory for the turbulent boundary layer in a compressible fluid (see R-403-PR). The calculations are explained in detail and tables of results are given, together with the JOSS program used in obtaining them. The study also includes a discussion and interpretation of Coles' classic theory. 60 pp. Refs.