Since Einstein's time, a theory of everything -- one coherent mathematical model that would encompass all the forces and particles of nature -- has become the Holy Grail of physics, and its pursuit has resulted in some of the most extraordinary ideas in the history of science. This invaluable primer at last enables all of us to understand these ideas. John Gribbin provides a brief, succinct, accessible overview of the hundred-year saga of particle physics, explaining everything from the basics (how subatomic particles work) to the cutting-edge research that has produced dazzling new models of the universe, among them the radical theories of superstrings -- the hypothesis that particles are loops of vibrating string -- and supersymmetry.