A thorough comparative study of the conditions of medieval Jewish life in Christian and Muslim lands. Cohen (Near Eastern Studies/Princeton) explores and explodes the recently resurrected myth of Arabs and Jews living in an ``interfaith utopia,'' especially during the centuries of Islam's ascendancy. This fantasy of a tolerant Golden Age in Spain before 1492 (when Jews were expelled) is (European) Jewish in origin, but it gets a lot of spin from propagandists trying to show that Muslims can be anti-Zionists but have never been anti-Jewish. Among the scores of primary sources quoted here is a letter from Jewish philosopher-physician Maimonides (d. 1204), who writes that ``none has matched [Islam] in debasing and humiliating us.'' Cohen modifies such statements and battles the ``countermyth'' of Arab savagery held by contemporary Sephardic Jews, who he views as competing with their Holocaust-surviving Ashkenazic counterparts. Before the 17th century, the frequency and harshness of both Christian and Muslim persecution is about equal, but Cohen deftly differentiates between the behavior of these two hosts by studying the particular economic and social conditions of various Jewish communities under different caliphs and kings. He analyzes all the decrees (Jews had to rise in the presence of Muslims) and restrictions (Jews could not own Christian land) with condiderable historical and theological insight. Early Christians, facing life- and-death competition with Jews in the Roman empire, developed an adversarial faith that ``fulfilled'' Judaism and ``demonized'' Jews. Consequently, treatment of Jews in Christendom ranged from serfdom to expulsion. Mohammed's minions had no ongoing struggle with Arabia's quickly subjugated Jews, hence Christian and Jewish ``people of the book'' were ``second-class subjects'' but allowed some occupational diversity. For an academic study of the Middle Ages, remarkably accessible and timely.