The God Equation: The Quest for a Theory of Everything is theoretical physicist Michio Kaku's accessible history of physics' oldest ambition, to describe every force and particle in nature with a single, unified set of laws. Kaku, a professor at the City College of New York and a co-founder of string field theory, frames the story as a sequence of great unifications. Isaac Newton joined the physics of the heavens and the Earth; James Clerk Maxwell united electricity and magnetism and revealed light as an electromagnetic wave; Albert Einstein recast gravity as the curvature of space and time; and the founders of quantum mechanics and the Standard Model explained the subatomic world and three of nature's four fundamental forces.
The remaining obstacle, Kaku explains, is that general relativity and quantum theory, each spectacularly successful in its own domain, are mathematically incompatible, and the conflict becomes acute at the center of black holes and at the moment of the Big Bang. He walks readers through the leading candidate for reconciling them, string theory, which proposes that particles are vibrations of tiny strings in a higher-dimensional space, and he takes up the controversies surrounding it, including the difficulty of testing it experimentally and the rival approaches its critics prefer. Along the way he addresses questions about what preceded the Big Bang, whether parallel universes exist, and whether time travel is possible. Brief and largely free of equations, the book offers a lucid overview of modern fundamental physics, written by an unabashed advocate who believes a final theory is within reach.