To Carolyn Conger "What really interests me is whether God had any choice in the creation of the world." ALBERT EINSTEIN "Deep in the chaotic regime, slight changes in structure almost always cause vast changes in behavior. Complex controllable behavior seems precluded." STUART KAUFFMAN "Sequelae are inherently unpredictable." IAN MALCOLM Introduction: "Extinction at the K-T Boundary" The late twentieth century has witnessed a remarkable growth in scientific interest in the subject of extinction. It is hardly a new subject - Baron Georges Cuvier had first demonstrated that species became extinct back in 1786, not long after the American Revolution. Thus the fact of extinction had been accepted by scientists for nearly three-quarters of a century before Darwin put forth his theory of evolution. And after Darwin, the many controversies that swirled around his theory did not often concern issues of extinction. On the contrary, extinction was generally considered as unremarkable as a car running out of gas. Extinction was simply proof of failure to adapt. How species adapted was intensely studied and fiercely debated. But the fact that some species failed was hardly given a second thought. What was there to say about it? However, beginning in the 1970s, two developments began to focus attention on extinction in a new way. The