The advance of scienti?c thought in ways resembles biological and geologic transformation: long periods of gradual change punctuated by episodes of radical upheaval. Twentieth century physics witnessed at least three major shifts relativity, quantum mechanics and chaos theory as well many lesser ones. Now, st early in the 21, another shift appears imminent, this one involving the second law of thermodynamics. Over the last 20 years the absolute status of the second law has come under increased scrutiny, more than during any other period its 180-year history. Since the early 1980 s, roughly 50...