Quotes from book
The Thirteenth Tribe

Name: The Thirteenth Tribe
Author: Arthur Koestler

The Thirteenth Tribe is a 1976 book by Arthur Koestler, in which the author advances the thesis that Ashkenazi Jews are not descended from the historical Israelites of antiquity, but from Khazars, a Turkic people. Koestler hypothesized that the Khazars migrated westwards into Eastern Europe in the 12th and 13th centuries when the Khazar Empire was collapsing.

“[T]he evidence from anthropology concurs with history in refuting the popular belief in a Jewish race descended from the biblical tribe. From the anthropologist's point of view, two groups of facts militate against this belief: the wide diversity of Jews with regard to physical characteristics, and their similarity to the Gentile population amidst whom they live. Both are reflected in the statistics about bodily height, cranial index, blood-groups, hair and eye colour, etc. Whichever of these anthropological criteria is taken as an indicator, it shows a greater similarity between Jews and their Gentile host-nation than between Jews living in different countries. …The obvious biological explanation for both phenomena is miscegenation, which took different forms in different historical situations: intermarriage, large-scale proselytizing, rape as a constant (legalized or tolerated) accompaniment of war and pogrom.”

Arthur Koestler book The Thirteenth Tribe

The Thirteenth Tribe (1976).