What if the speed of light—now accepted as one of the unchanging foundations of modern physics—were not constant? Brilliant young physicist João Magueijo puts forth the heretical idea that light once traveled faster, in the very early days of the universe—an idea that may dethrone Einstein and forever change our understanding of the universe. Solving the most intractable problems of cosmology in one brilliant leap, Magueijo’s varying-speed-of-light theory (VSL) could have truly marvelous implications for space travel, black holes, time dilation, and string theory—and could help uncover the grand unified theory that ultimately eluded Einstein. Faster Than the Speed of Light tells the remarkable story of Magueijo’s struggle to understand how the universe works, to challenge long-established ideas, and to fight to have his bold new vision accepted.