This new paperback edition celebrates the centennial of the birth of one of the major theoretical physicists of our time. It is an engrossing account of an exciting period in history and science as well as a good introduction to nuclear physics for the nonscientist. Moving from Bohr's first great contribution - a description of what is essentially the modern picture of the atom, in 1913, for which he won the Nobel Prize in 1922 - the book covers his creation of one of the most productive research institutes of the modern period. It also describes his less well known political work before and during World War II, when Bohr first helped colleagues escape from Italy and Germany, and then returned to Denmark to participate in the anti-Nazi movement; and at war's end, when he worked toward a vision of a world free from the dangers of nuclear war. Ruth Moore is a science feature writer for the Chicago Sunday Times. She is the author of several popular science books, including Man, Time, and Fossils: The Story of Evolution and Charles Darwin: A Great Life in Brief.