In the western suburbs of Istanbul, the site of Küçükçekmece is known since one century as yielding a late Miocene vertebrate fauna. In 1933, Malik and Nafiz provided the first detailed study. Later, new discoveries came to enlarge the collections housed at two universities of Istanbul and at the Paris Museum. The present volume provides a detailed systematic study of all mammalian fossils housed in these collections, completed by a chapter on the geology and stratigraphy, and another on the historical background of paleontological investigations in the Istanbul region. The Küçükçekmece fauna is remarkable by the high diversity of mammals, dominated by eleven species of ruminants (tragulids, cervids, giraffids, bovids) and nine carnivores, in addition to several rhinos, equids, chalicotheres, proboscideans, suids, aardvarks, insectivores, lagomorphs and rodents. This site is also remarkable in yielding both terrestrial and marine mammals, indication a near shore depositional environment. Thanks to the present study, Küçükçekmece is therefore a new hotspot of mammalian biodiversity at some nine millions years ago on the crossroads between the three main landmasses of the Old World.