Measurements of the peculiar motions of galaxies are proving to be one of our most direct probes of the large-scale distribution of matter in the local universe. This information bears on a variety of issues, including the amount and nature of dark matter and the birth and evolution of structure in the universe in the context of the big bang model. The research to be conducted with this grant will involve an observational program to measure improved distances to galaxies. This will provide peculiar motions of unprecedented accuracy for a sample of hundreds of galaxies spread over a significant volume of space. The availability of such data should allow a much more detailed and relatively bias-free map of the distribution of dark matter. Such a map is essential for evaluating the ability of numerical models of structure formation to simulate the real universe, and, through comparison with maps of the distribution of luminous galaxies, instructive as to the process of galaxy formation. The Principal Investigator is highly regarded for his research in this area.