While most people have heard of Albert Einstein, fewer people have heard of Niels Bohr, a fellow physicist who was friends (and rivals) with the great scientist. Niels Bohr had created new ways of looking at the world in the first half of the 20th century. With the Bohr atom, science began a journey that continues to amaze, disturb, and enlighten today. Under his stewardship the quantum revolution brought to light some of the finest minds of 20th-century physics, an astonishing group of brilliant and innovative scientists, who in turn sowed the ideas that have changed our world and the way that we understand it.