In this collaborative project, the PI's will use spectroscopy and photometry to measure the abundances of Li and other elements for hundreds of stars in seven open clusters, in order to constrain models of interior stellar structure. The collaborative component of the project will bring together photometry and spectroscopy expertise so that the investigators can address the mystery of anomalous Li abundances, which may indicate that additional, as yet unknown, physical mechanisms act in stars. Both PI?s have institutional access to appropriate observatories (WIYN and Mt. Laguna). The work will have broader impacts to Galactic evolution and cosmology, and the PI?s will train undergraduate and graduate students in research at two universities.