This research conducted fundamental investigations of turbulent mixing, chemical reaction and combustion processes in turbulent, subsonic and supersonic flows. This program is comprised of an experimental effort, an analytical effort, a computational effort, a modeling effort, and a diagnostics development and data-acquisition effort; the latter as dictated by specific needs of the experimental part of the overall program. Our approach has been to carry out a series of detailed theoretical and experimental studies primarily in two, well-defined, fundamentally important flow fields: free shear layers and axisymmetric jets. To elucidate molecular transport effects, experiments and theory concern themselves with both liquids and gases, primarily in moderate to high Reynolds number flows. Modeling has been focused on both shear layers and turbulent jets, with an effort to include the physics of the molecular transport processes, as well as formulations of models that permit the full chemical kinetics of the combustion process to be incorporated. Our recent analytical efforts have concentrated on a hydrodynamic analysis of the stability of compressible shear layers. The computational studies are, at present, focussed at fundamental issues pertaining to the computational simulation of both compressible and incompressible flows.