The Sinap Formation in central Turkey near the city of Ankara preserves a rich record of mammalian evolution from about 15 to 5 million years ago and is one of the few sites in this region that also has fossil apes. It is unique among other fossil localities from Europe to Western Asia in that it has a thick stratigraphic section and preserves a long record of geological time. The authors have been able to piece together a detailed record of faunal change and, by adding paleomagnetic and radiometric dating techniques, have produced a chronostratigraphy for the Formation. Because of the dual importance of the rich record of the fossils, and the dating of the sediments, the editors have been able to attract some of the leading authorities on Eurasian Neogene paleontology and geology to contribute to this reference work. The results from the Sinap Formation will be the template against which other sites from Europe to Asia are compared.