This brief, difficult and disturbing book covers the entire subject of the relationships between Judaism and Christianity, encompassing also the engagements of Jews with Christians and Christians with Jews. It is intellectually the most ambitious book on its topic that I know, and, rich in original ideas, it also is one of the most engaging. Even though I find its historical thesis wrong and its theological thesis racist, I also think that it should be read by everyone who wants to know why Judaism flourishes among Jews, and why Christianity's mission to Israel after the flesh, to the Jewish People, fails ignominiously.

Klinghoffer's historical thesis, announced in the title, is that Judaism could not have won over the vast populations that adopted Christianity, so that only Christianity Judaism without the law or Torah and Halakhah could have accomplished the civilizing mission that accomplished by Christianity yielded the Christian West. No advocate of Judaism has ever before written so shocking an indictment of Judaism, confirming the accusations of its most bitter enemies, for instance the apostle Paul and the prophet Muhammad, that it was a forbidden ethnic island with no message for humanity. And that is only one of Klinghoffer's propositions – no wonder it is a book with a troubling message.

Klinghoffer narrates the history of Jews and Judaism's response to Christianity, here meaning the claim that Jesus was and is the Messiah: “The disputation has been going on ever since, as I will show in this book the first to tell the story of this ancient debate in the form of a historical narrative. Beginning with how Judaism looked in the year immediately before Jesus initiated his ministry, we will tell the story of how Jews reacted to him as a teacher and provocateur, what role they may have played in his death, how they violently rejected the apostle Paul, how the debate about Jesus developed in the Talmudic and medieval periods, and how the disagreement continues down to the present”(p. 3). So much for the narrative of the book, which covers seven chapters and a conclusion: before Christ, Judaism in the year 27; first encounter, was Jesus the Messiah; fatal attraction, did the Jews kill Jesus?, a new religion, the curse of the Torah; after Christ, before Constantine, conversations with Minim; medieval minds, the great debate; modern times, the never-ending disputation; a kingdom of priests.

But while the narrative dominates, the thesis lies elsewhere: “What if in his lifetime tens or hundreds of thousands of Jews rallied to him?” Instead of turning to the gentiles, Jesus's followers would have continued “to be obligated in the biblical commandments of circumcision, Sabbath, kashrut, family purity and so on, the Jesus movement might have remained a Jewish sect. “Then…Christianity would not have spread wildly across the Roman Empire and later across Europe, as it did. Judaism was never designed to be a mass religion, its ways take careful meditation and definite commitment to appreciate their deeper joys. Had the Jews not rejected Jesus, the nascent faith would have perished along with all the other heterodox Jewish sects that disappeared after the destruction of Jerusalem. There would be no Christianity, no Christian Europe, and no Western civilization as we know it. Quite conceivably, Islam would have arisen more or less as it did, another offspring of Judaism that also dispensed with the complexities of Jewish religious practice.”

Klinghoffer's premise, that the ritual requirements of Judaism formed an obstacle to mass conversion, will have surprised the Maccabees, who offered the Galilaeans whom they conquered the choice of two knives: be slaughtered or be circumcized and Judaized Galilee. The cult of Mithra, which competed with Christianity quite successfully before the conversion of Rome's emperor to Christianity, involved a variety of religious rites, including a bath in the blood of an ox. More to the point, Islam sets forth religious obligations including a pilgrimage, dietary rules, prayer five times a day, not to mention circumcision at puberty. And yet, we see, Islam from the beginning was and is a mass religion. In its day Judaism conquered and converted, and so did Christianity and Islam. And Christianity in Jerusalem, taking shape around the figure of Jesus's brother, James, saw no obstacle in Halakhic Judaism to success. The reason Judaism in antiquity lost the competition with Christianity was the political disasters brought on by the two unsuccessful wars against Rome, 66–73 and 132–135, and the political triumph of Christianity in the conversion of the emperor Constantine. From that point, Judaism could not convert masses of pagans, and its subordinated status in Christendom and Islam, not its supposedly ethnic insularity (as Paul and Muhammad thought), formed a barrier to the dissemination of its universal message.

I left for the end the theological thesis, which I called racist. Carrying forward ideas of Martin Buber, Klinghoffer's conclusion, is that the Jews reject Jesus because of “the mystic uniqueness of the Jewish essence or nature…there is something distinct about the Jewish soul.” The Jewish soul is “unique in two ways. First, by its nature it sees God as at once beyond the grasp of man and yet present in an immediate relationship with these human beings. Second, also by nature the Jewish soul feels the worlds, in a remarkably visceral way, as unredeemed.” On this view, how can gentiles convert to Judaism, and how can Jews opt for secularism, Buddhism, or Christianity? Such things would be contrary to their nature.

In a bit more than two hundred pages, Klinghoffer has managed to raise fundamental issues of human existence as embodied in Israel, the holy people. That is why I find the book so disturbing.