Michio Kaku, renowned theoretical physicist and New York Times bestselling author of Hyperspace and The Future of Humanity, tells the story of the greatest quest in all of science.When Newton discovered the laws of motion and gravity, he unified the rules of heaven and earth. From then on, physicists have been discovering new forces and incorporating them into ever-greater theories. But the major breakthroughs of the twentieth century--relativity and quantum mechanics--are in