The proceedings of the 20th annual Montreal-Rochester-Syracuse-Toronto conference on high energy theory provide an overview of recent advances in elementary particle theory, including gravitation, collider physics, heavy quark systems, physics beyond the Standard Model, 2-d field theories, technicolor, supersymmetry, and string theory. The common thread linking these ideas is the quest for a fundamental, unified theory, sometimes called "the theory of everything." MRST is unique in providing an overview of the exciting advances toward this ultimate theory from diverse directions, yet in a concise volume whose contributions are meant to be accessible to a general particle physics audience.