This three-year continuing grant supports the work of Christopher Davis, University of Louisville, on Fermilab Experiment 672. This is an experimental study of dimuon production is hadron-proton and hadron-nucleus collisions at high energies. The experiment will study several QCD subprocesses which contribute to the interaction. This experiment will lead to greater understanding of the "strong" force which binds quarks together to form protons and neutrons and which holds these together in nuclei.