Bohr was a peculiar kind of sage—brilliant and insightful, yet plodding and obscure, sometimes infuriatingly so. “It is practically impossible to describe Niels Bohr to a person who has never worked with him,” said George Gamow, a Russian physicist and former student of Bohr (who had a famously large personality himself). “Probably his most characteristic property was the slowness of his thinking and comprehension.”