  String theory and supersymmetry are theoretical ideas that go beyond the
standard model of particle physics and show promise for unifying all forces.
After a brief introduction to supersymmetry, we discuss the prospects for its
experimental discovery in the near future. We then show how the magic of
supersymmetry allows us to solve certain quantum field theories exactly, thus
leading to new insights about field theory dynamics related to
electric-magnetic duality. The discussion of superstring theory starts with its
perturbation expansion, which exhibits new features including ``stringy
geometry.'' We then turn to more recent non-perturbative developments. Using
new dualities, all known superstring theories are unified, and their strong
coupling behavior is clarified. A central ingredient is the existence of
extended objects called branes.
