IN modern hypersonic programs it has been recognized from the outset that computational fluid dynamics (CFD) must play a major role. Indeed, the future of high-speed air and space transportation depends critically on our ability to predict solutions of those aerothermal problems which are too difficult or expensive to test in ground-based simulation facilities. Great strides have recently been made in the ability of CFD methods to do this, but it is clear that substantial improvement is still needed. Although not the only problem obstructing further advances in CFD, turbulence modeling is recognized to be one of the major ones. A closed solution of the governing Navier-Stokes equations for turbulent flows of practical consequence is still far beyond our grasp. At the same time, the simplified models of turbulence which are used to achieve closure of the Navier-Stokes equations are known to be rigorously incorrect. Although these models serve a definite purpose, they are inadequate for the general prediction of viscous/inviscid interactions, compressible turbulent mixing, transition, chemical nonequilibrium, and a range of other phenomena which must be predictable in order to design a hypersonic vehicle computationally. For this reason, turbulence modeling is a key issue in the continuing effort to push forward the boundaries of knowledge of high-speed flight. Because of the complexity of turbulence, useful new turbulence models are synthesized only when great expertise is brought to bear and considerable intellectual energy is expended. Although this process is fundamentally theoretical, crucial guidance may be gained from carefully executed basic experiments. Following the birth of a new model, its testing and validation once again demand comparisons with data of unimpeachable quality. This report concerns these issues, which arise from the experimental aspect of turbulence modeling for high-speed flows. A high-speed turbulence modeling workshop was held at NASA Ames Research Center, June 7 and 8, 1988. This workshop had the goal of identifying ways to improve turbulence modeling for hypersonic flows, with specific applicability to the NASP program. Both theoretical and experimental issues were discussed in detail. In the course of this discussion, questions arose about the quantity