Mark Cohen's comparative study of the status of Jews under Christendom and Islam during the Middle Ages is the most sophisticated, nuanced, meticulous, and persuasively-argued study of its kind. The extremely negative customer review on this page betrays the bias of its author. Citing from Bat Ye'or to demonstrate that the Jewish position in Islam has always been wretched is an exercise in futility. Bat Ye'or is anti-Muslim to an extreme. She thanks "Judeo-Christian" values for the positive treatment Jews currently receive at the hands of the post-Holocaust Western world. As if the previous 1800 years of expulsions, libels, massacres, burnings at the stake, forced conversions, and genocidal attacks pursued in various periods by elements (i.e. states or populaces) loyal to the Catholic Church, the various Eastern Orthodox Churches and, in its first two hundred years, the Protestant Churches as well, never occurred or are somehow irrelevant. It was rather the separation of church and state that resulted from the 18th century Enlightenment that allowed for the fair treatment Jews currently experience in Western countries, although that too must be modified by the brutal pogroms in Russia in which thousands of Jewish men, women, and children were slaughtered, as well as the Holocaust perpetrated by European Christians, some of whom (such as in Croatia) were religious, though most were not.
When thousands of Jews across Europe were being burned alive on the streets during the Black Plague (1348 and further), Jews in Muslim lands were able to live and practice their religion, without fear that the local Muslim populations would associate them with the devil and kill them on the basis of outlandish libels. The example of the Black Plague is particularly illustrative of the gap between the medieval Jewish experience under Islam and Christendom, since the Muslim lands were stricken as heavily by this epidemic as the Christian lands, and yet there is not one single recorded instance of Muslims accusing Jews of having been responsible for the plague, whereas in Christian Europe it was just this accusation that was so widespread and consistently served as a pretext for large-scale massacres of Jews. Sure, there were instances of persecution of Jews in Muslim lands, but they were few and far between, and the most significant of the limited number of such persecutions were carried out by heteredox sects such as the fanatical Almohades (Spain, 12th century) and the Caliph al-Hakim (Egypt, Palestine, early 11th century), who was clearly deranged in the most literal sense in the view of most historians. The fact that Jews were discriminated against throughout the Muslim world must be understood in the context of its time: in the Middle Ages, tolerance was not regarded as a virtue, but a weakness, and no one practiced it in the modern sense of the term. Without any doubt, the protected status accorded Jews in return for payment of the discriminatory taxes and other regulations was far better than their brothers in Christian Europe could imagine. Cohen cites numerous primary sources that demonstrate that the self-perception of medieval Jews themselves was that Muslims did not buy into the absurd accusations hurled against Jews in Christendom and that the Jewish experience under Islam was not regarded as "galut" (exile) in the same sense in which it was in Christendom.
If there is any flaw in Cohen's book, it is in his ambiguously-worded statement on the very last page which might seem to suggest that the thirteenth century marked a new era for Jews under Islam, one that might perhaps (though Cohen doesn't say this) rival Jewish life in Christendom. Many of Cohen's own citations and much of his argumentation make it clear that this is not the case, and that instead Jews continued to experience a far more secure existence under Islam until the advent of the modern period of Jewish history (i.e. the 18th century) than they did in Christendom, though they were less secure than they had been in the classical period of Islam. This point will be clear to those familiar with the widespread massacres of the 14th century in Northern Europe, the continued persistence of the blood libel in Europe (absent in Islam), the Spanish Inquisition (including the pogroms that preceded it by a century), the expulsions and massacres following the Protestant Reformation, and the massacres of the 1648-1649 Cossack uprising--and the lack of such horrors in the lands of Islam. This is particularly true of the Ottoman Empire, which was a safe haven for Jews in the 16th and 17th centuries (though Catholic Poland was as well). It is just such nuances (i.e. sometimes Jews were persecuted in Muslim lands and sometimes they found haven in Christian lands) which are missed by advocates of what Cohen terms the "countermyth" of Islamic persecution, like Bat Ye'or. (The original "myth" debunked by Cohen is that Jewish life under Islam was an interfaith utopia when, in reality, Jews were always second-class citizens subject to hardships, though they sometimes rose above that position, as in Muslim Spain during the so-called "Golden Age.") Mainstream scholars such as Bernard Lewis, S. D. Goitein, and Cohen himself reject with equal vigor both myths. This nuanced approach is too complicated for people like Bat Ye'or (and Robert Spencer), who think things had to always have been how they are now.
In short, people like Bat Ye'or are engaged in projectionism of the worst kind: the Muslim world today is teeming with the most virulent anti-Semitism imaginable, so it must have always been that way. However, history doesn't work that way. Trends change; the job of the historian is to analyze them dispassionately, which Bat Ye'or, having been expelled from Egypt in a humiliating fashion in the 1950s, is apparently not capable of. (In fact, it is the consensus of historians that anti-Semitism in its conventional sense did not exist in the Muslim world until modern times and that it was only introduced into it by Christian Arabs in the 19th cenury. See p. 208, note 28 of Cohen's book for sources.) As for the other methodological issues raised in the negative customer review, Cohen's book is so meticulous that all of these issues are treated by Cohen himself, some in the very Introdction to his book! Read the book and see for yourself. Just don't be taken in by polemicists who are more concerned with creating simple answers to complex problems (i.e. why did Jewish-Muslim relations deteriorate in the modern period?) than in analyzing history.