Between them, Jeffrey H. Schwartz and Ian Tattersall have published nearly 400 articles and 20 books on various aspects of primate, including human evolution. In addition, they have published extensively on topics in evolutionary theory: Dr. Schwartz on development and the origin of evolutionary novelty, and Dr. Tattersall on species recognition. Dr. Schwartz has also been involved in the recovery and analysis of human and animal skeletal remains on archaeological sites, and Dr. Tattersall in the study of lemur behavior and ecology. They have collaborated since 1972 on projects dealing with the evolutionary relationships of living and fossil lemurs, and have been pursuing their current study of the human fossil record since 1994, travelling the world to gain photographs and details of every specimen possible. Dr. Schwartz's latest book is Sudden Origins: Fossils, Genes, and the Emergence of Species (Wiley), while Dr. Tattersall recently published The Monkey in the Mirror: Essays on the Science of Becoming Human (Harcourt). They also recently co-authored Extinct Humans (Westview).