The Mass-Extinction Debates is the first to examine the arguments and behavior of the scientists who have been locked in conflict for a decade over two competing hypotheses for the cause of the mass extinction, some 65 million years ago, of most of life on earth, including the dinosaurs. These papers – by historians, sociologists, philosophers, and participating scientists – provide an exceptional opportunity to observe firsthand the workings of science that in quieter times are hidden from view. The Mass-Extinction Debates concludes with an overarching discussion by a balanced panel of embattled scientists and scholars.