At a moment of great discovery, one Big Idea can change the world...Niels Bohr's discoveries in quantum theory led to advances in physics and our understanding of atomic structure. His work won him the Nobel Prize in 1922 and his ideas continue to propel physics towards new discoveries. But what is quantum theory? Most of us do not understand even the basics of one of the most significant scientific advances ever made, opening up a whole new field in science, whose ambiguities still challenge scientists around the world. "Bohr and Quantum Theory" offers an accessible and absorbing account of the man who was both a part of The Manhattan Project but also an advocate of peace. He held the key to understanding such intricate realities as black holes and nuclear energy. Bohr's Big Idea explains complex and crucial ideas in a clear and engaging way, placing quantum theory in the context of a man's life, work and time and examining its important implications for our future. "The Big Idea" series is a fascinating look at the greatest advances in our scientific history, and at the men and women who made these fundamental breakthroughs.