As Roland perceptively noted, Sand's book is not so much propositive of a theory, as deconstructive of theories about a people. The most invaluable part of the book consists of a perfectly normal historian's history, i.e., of the socio-ideological forces influencing the construction of a modern collective Jewish identity. In this I am reminded of Martin Bernal. His propositive theory, which however took up far more space than Sand dedicates to the Khazars, was almost self-evidently silly. But his analysis in volume 1 of the modern historiography of ancient Greece as that was influenced by racial theory, is still regarded as a tour de force. One doesn't throw the baby out with the barfwater. As to genetics, Sand himself deals with that pp.273ff., and in so far as RS reviews challenge him on this, they cannot be excluded, even if, it's just a personal view, many of those reviews are incompetent and show a lack of familiarity with the book. The criterion should be, genetic criticism or evaluation of Sand should be admitted if Sand's book is specifically targeted or mentioned by those papers, and ignored if not. What should not happen is the application of a double-standard.