Neanderthals first appeared in Europe and western Asia between 300,000 and 400,000 years ago. They are our closest (extinct) relative, and their species survived until 30,000 to 40,000 years ago, when they vanish from the fossil record, says Svante Paabo, director of the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, and author of "Neanderthal Man: In Search of Lost Genomes." Why these relatives of ours thrived for so long and then ended their long, successful run about the same time that modern humans