It is now recognized that more than 50% of the stars in our Galaxy are in binary systems. Some of these binary stars are contact binaries, meaning that their atmospheres are in contact and that the two stars interact strongly (tidal interactions, mass transfer). The Principal Investigator proposes in this Research in Undergraduate Institutions (RUI) proposal to observe a relatively homogenous sample of contact binaries with the aim of determining 1. their masses ratios, radii, and luminosities and 2. testing current theories of the origin and evolution of these systems.