I read his book back then and was very impressed. But his Khazar theory has been debunked since then. I think DNA tests have been used on this.
The only people still going on about European Jews being Kahars are anti-Semites and internet nut cases. Muslims possess no logical thinking so they love Kahzar mythology and using it against Israel and other Jews.
The Khazars www.csjo.org/pages/essays/essaykhazars.htm The greatest evidence against a significant Khazar ancestry for Ashkenazic Jews is DNA testing. Data shows that the predominant origin of Ashkenazic Jews ...
It isn't just antisemites who like to call Jews Khazars. There are some Russophile Jews who like to claim to be Khazars. Their Facebook group is interesting. They have't quite ever bothered to check out Russian history, or they would know that the Khazars wer the bogey men for the first 200 years, to say nothing of Soviet revisionism that had Khazars as the 1% and Varangians being the revolutionary vanguard of a slavic revolt against their oppressors. This was pretty much Stalin's theory.