Research in theoretical physics will cover a wide variety of topics, including superstring and supersymmetry theory, lattice field theory, perturbative quantum chromodynamics, collisions involving elementary particles, collisions involving nuclei, statistical mechanics, and problems at the interface between classical and quantum mechanics. This broad research program includes efforts to unify our description of all the forces, attempts to better understand the behavior of the elementary particles, and studies which illuminate basic physical principles by revealing their consequences in interesting physical situations.