Perhaps the two most important conceptual breakthroughs in twentieth century physics are relativity and quantum mechanics. Developing a theory that combines the two seamlessly is a difficult and ongoing challenge. This accessible book contains intriguing explorations of this theme by the distinguish...

Perhaps the two most important conceptual breakthroughs in twentieth century physics are relativity and quantum mechanics. Developing a theory that combines the two seamlessly is a difficult and ongoing challenge. This accessible book contains intriguing explorations of this theme by the distinguished physicists Richard Feynman and Steven Weinberg.