9409793 Boesgaard Observations will be made to determine the abundances of the light elements lithium, beryllium and oxygen in stars and in the interstellar gas. The abundances of lithium and beryllium in the oldest stars gives information on inhomogenieties in the early universe while the beryllium and oxygen abundances in stars of various ages hold clues to the way in which elements formed as the galaxy aged. Both lithium and beryllium will be used to test mechanisms which operate within stars. This research will take advantage of new technical developments in astronomical detectors and new theoretical advances in stellar atmospheres, stellar interiors and Big Bang nucleosynthesis. ***