The Thirteenth Tribe is a ground breaking work of great importance, if only because it has shaped the way that people think about The Jews. It is based on the theory that European Jews, Ashkenazi Jews from Europe, are not descendants of Abraham but rather are the remnants of a tribe, the Khazars, that converted to Judaism in the Eighth Century. We know little about the Khazars, but we do know for certain that they existed and that they were Jewish. The Jews, Russians, Georgians and Armenians all wrote about the Khazars, but the Khazars left no literature, no books. This was perhaps because the Khazars existed during the Dark Ages, a period from which few books survive today. Koestler's thesis is that while the Khazars as a unified tribe may have disappeared, their descendants survived, only that they were no longer known as the Khazars. Instead, these people are now Eastern European Jews and they continue to live in the same places where the Khazars lived such as in Kiev and Odessa. The view of Arthur Koestler who himself was Jewish is that none of the mass movements of the Jewish people happened at all. Rather, the Jews stayed in exactly the same place where they have been all along because the Eastern European Jews are the Khazars. They are the same people. Just their name has been changed. Which is more logical: The Traditional Jewish view or Arthur Koestler's theory?