Extinction: Bad Genes or Bad Luck?

Raup takes up a cocktail-party science topic--Why do entire branches of life ``suddenly'' (in geologic time) disappear?--and gives it weight and validity. Despite the catchy title, Raup's presentation is plenty rigorous, drawing in just enough geology, anthropology, biostatistics and yes, even the Alvarez meteor/earth cataclysm, to send readers looking for additional reading on current evolutionary theory. Fans of Stephen Jay Gould will find a similarly fluent and friendly lecture style here. University of Chicago professor Raup is coauthor of several standard graduate-level texts on paleontology and evolution. Illustrations not seen by PW. (Sept . )