As a zealous Catholic adolescent, I once met with this rebuff from a Jewish acquaintance: "What was new in Christianity was not good, and what was good was not new." At the time, I was too scandalized to ask what he meant; later in life, it ceased to matter. But now, after reading The Mythmaker and Hyam Maccoby's earlier book, Revolution in Judea, I understand what my friend meant, and I couldn't agree more.

The traditional Christian account of Jesus goes something like this. He was a Divine Being (or, according to liberal Protestants, a divinely inspired man); he came to transform legalistic, particularistic Judaism into a universal religion of love and grace; he was bitterly opposed by the narrow-minded, self-righteous Pharisees, who handed him over to the Romans on trumped-up political charges; and after his death, the Jews rejected his teaching and persecuted his followers. One of the chief persecutors, the Pharisee Saul, had a vision on the road to Damascus and became St. Paul, Apostle to the Gentiles, the most authoritative exponent of Jesus's new dispensation.

According to Maccoby, all of the above is bosh. Jesus was a devout Jew. He was, in fact, a Pharisee, and his relations with other Pharisees were cordial. He had no intention of transforming Judaism, which was in any case a far cry from the rigid, ritualistic creed portrayed in the Gospels. He was, however, a revolutionary. Like every other pious Jew of his time, he opposed the brutal Roman occupation; and like several other popular Jewish teacher-activists in the 1st century, he proclaimed himself the Messiah, God's special instrument of Jewish national liberation. For this he was denounced by the religious establishment, the quisling Sadduces, to their Roman masters, who executed him as a subversive. His followers kept hoping that he would return as part of a divine intervention to oust the Romans and inaugurate "the kingdom of God," i.e., Jewish independence and world peace. They were seriously annoyed when the upstart Paul began misrepresenting Jesus far and wide in order to build up a personal following and launch a new cult. But their attempts to discipline him came to an end, along with their political hopes and, in most cases, their lives, when in 70 AD the Romans responded to an insurrection in Judea with mass executions, wholesale deportations, and the physical destruction of Jewish society. After that, Paul had the field to himself.

Who was Paul, anyway? According to the New Testament, he began as a dedicated Pharisee, appalled by Jesus's religious innovations and determined to stamp them out. But after his conversion, he atoned for his previous sectarianism by undertaking to bring Jesus's message to the Gentiles, which he did with St. Peter's blessing and with spectacular success.

More bosh. The Pharisees, as noted, were sympathetic to Jesus and, like him, were religious nationalists. Paul was not a Pharisee and actually demonstrated a very imperfect understanding of rabbinical Judaism, which was a much livelier and more humane affair than he made out. He was, by his own admission, an agent of the Sadducee High Priest, who was a Roman collaborator loathed by the Jewish population. But in spite of his unsavory activities, Paul was a complex, tormented soul, and his "conversion" was indeed momentous. What sprang from his fevered brain on the road to Damascus was, Maccoby writes, "an imaginative creation of tremendous poetic power."

The 1st-century Mediterranean world was seething with spiritual movements. The two most popular were Gnosticism and the mystery cults. Gnosticism was dualistic and antinomian: it saw the material world as ontologically evil, created by a Demiurge and ruled by dark forces, into which a remote and beneficent God occasionally sent messengers bearing secret knowledge (gnosis). This knowledge, not morality or law, was the key to salvation. The mystery religions taught that the world was to be redeemed by the incarnation, suffering, death, and resurrection of the god himself: Attis, Adonis, Osiris, Baal, et al. The Epistles of Paul are riddled with similar motifs: the fundamental sinfulness of this world; the abrogation of the law by a divine messenger bearing higher knowledge; the redemptive power of a divine sacrifice. Maccoby claims that Paul, in a brilliant, epochal move, fused elements of Gnosticism and the mystery cults with Judaic rationalism and historicism. The resulting religious myth -- Christianity -- captured the imagination of the Hellenistic world and became, for better or worse, the basis of European culture. This myth was propagated by the Gospels, which were written by Paul's admirers and associates and contain, along with a residue of historical truth, sweeping falsifications of Jesus's life and of 1st-century Judaism. Christian anti-Semitism was thus not merely an unfortunate by-product of the New Testament, but an essential part of its purpose.

Is all this really true? I suspect it is. We will never know precisely who Jesus was, what he said, or what he meant: the evidence is too fragmentary. But Maccoby builds his case on centuries of Talmudic and New Testament scholarship; and his reasoning, though daring, is scrupulous. As detail after detail of his interpretation falls into place, the thesis that emerges is overpowering in its scope and coherence. It may still be bosh, of course. But I don't think so.