The results of a detailed experimental investigation of the compressible turbulent boundary layer in a zero-pressure-gradient flow are presented for zero, moderate and severe heat-transfer conditions. The studies were conducted on a flat nozzle wall for a nominal Mach number of 4.9, at momentum thickness Reynolds numbers from 7,000. to 58,000. and at wall-to-adiabatic-wall temperature ratios of 1.0, 0.8 and 0.25. Complete profile measurements were taken with Pitot pressure probes and conical-equilibrium and fine-wire temperature probes. Furthermore, the wall shear and surface heat transfer were measured directly with a skin-friction balance and a heat-transfer gage, respectively. (Author Modified Abstract).