[Mr. Karsh is head of Mediterranean and Middle Eastern Studies at King’s College, University of London, and author of “Fabricating Israeli History: The ‘New Historians.’”]

Benny Morris, the Israeli “new historian,” probably doesn’t know it, but it was his book on “The Birth of the Palestinian Refugee Problem” (1987) that led me more than a decade ago to temporarily shelve my research into the history of Islam and the Middle East and join the debate on the origin of the Israeli-Palestinian conflict.

This happened when, purely by accident, I noticed a glaring contradiction between the English and Hebrew renditions of an October 1937 letter from David Ben-Gurion to his son. The English version had Ben-Gurion say: “We must expel Arabs and take their places”; the Hebrew edition represented him as saying precisely the opposite. An examination of the original document unequivocally settled the matter. It read: “We do not wish and do not need to expel Arabs and take their place. All our aspiration is built on the assumption — proven throughout all our activity — that there is enough room in the country for ourselves and the Arabs.”

To ascertain whether this was an isolated case of misrepresentation or a pervasive phenomenon, I undertook to carefully examine all the documentation used by Mr. Morris with regard to early Zionist attitudes toward the Arabs. In quick time, I was taken aback by the systematic falsification of evidence aimed at casting Zionism as “a colonizing and expansionist ideology and movement ... intent on politically, or even physically, dispossessing and supplanting the Arabs.” This ranged from the more “innocent” act of reading into documents what was not there, to tendentious truncation of source material in a way that distorted its original meaning, to rewriting of original texts to say what they did not mean, as he did with Ben-Gurion’s aforementioned letter.

As our exchanges reached ever-growing audiences, Mr. Morris was forced to concede that his “treatment of transfer thinking before 1948 was, indeed, superficial,” and that he had “stretched” evidence to make his point. He also removed, in an implicit acknowledgment of their inaccuracy, some of the most egregious misquotes about transfer in “The Birth,” and admitted that in writing the book, he had not “had access” to — elsewhere, he says he “was not aware of” — the voluminous documents in the archives of the Israeli institutions whose actions in 1948 formed the main part of his indictment.

This, nevertheless, did not prevent him from claiming, in a revised edition of “The Birth” published in 2004, that “the displacement of Arabs from Palestine or from areas of Palestine that would become the Jewish State was inherent in Zionist ideology” and could be traced back not only to the 1930s, as he claimed before, but to the father of political Zionism, Theodor Herzl. (True to nature, Mr. Morris based his charge on a truncated paragraph from Herzl’s diary, which had already been a feature of Palestinian propaganda for decades, and which referred not to Palestine but rather to Argentina, considered at the time by Herzl as the future site of Jewish resettlement.)

It is doubtful whether Mr. Morris even believed his own thesis. Certainly, in numerous press articles and media appearances over the past eight years, he has totally reversed the core of his historical narrative, claiming that while “the Zionist movement agreed to give up its dream of ‘Greater Israel’ and to divide Palestine with the Arabs” as long ago as the 1930s and ’40s, “the Palestinian national movement, from its inception, has denied the Zionist movement any legitimacy and stuck fast to the vision of a ‘Greater Palestine,’ meaning a Muslim-Arab populated and Arab-controlled state in all of Palestine.”...