Written and edited by southeast Asia-based academic Priscilla Roberts, it attempts to be even-handed and there is little that is offensive or too inaccurate (it certainly has mistakes.)
But when I searched the book for "antisemitism," it mentions only the European version. It says nothing about Arab antisemitism. It doesn't have a separate entry on the Mufti of Jerusalem and his virulent hate nor anything about his Nazi collaboration. It mentions the Hebron pogrom of 1929 only as an aside in the article on United Kingdom Middle East policy: "Sporadic armed conflict between the two communities simmered until, in August 1929, 67 Jews were murdered by rioters in Hebron. This shocking event eroded what little confidence Jewish leaders had in a binational compromise future for the region and led to the rapid expansion of the paramilitary Jewish self-defense force known as the Haganah."
Throughout the book, Arab antipathy towards Jews is framed as a logical response to Zionism and the history of Islamic and Arab antisemitism is simply not there.
This is what we see in the media as well as academia. Jew-hatred is fundamentally irrational and no one wants to accuse Arabs or Muslims of being irrational, because that sounds Orientalist. Ignoring the very real history of antipathy towards Jews in the Arab world is not doing anyone any favors, though - if one ignores a fundamental reason for the conflict, one cannot possibly pretend to explain it.
Since the beginning of Islam, Jews were regarded as dhimmis in Muslim-majority (mostly Arab) lands. They were second class citizens with limited rights. They were tolerated, mostly, as long as they kept in their place. When they were perceived as having crossed some imaginary line, they were subjected to pogroms no less violent than those in eastern Europe. And the very existence of a Jewish state in the midst of Arab lands is hated not because of pro-Palestinian sentiment: it is from the shame that the weak, hated, dhimmi Jews defeated the combined Arab armies.
To ignore that history in describing the Arab Israeli conflict is to effectively censor an important narrative. Even worse, it ignores the antisemitism that is still seen in Arab media, today.
Roberts worked with a larger team on the four volume 2008 "The Encyclopedia of The Arab-Israeli Conflict: A Political, Social, and Military History" which is also online. In that work, Arab antisemitism is not ignored, but it is minimized.
Its entry on antisemitism concentrates on how historic European antisemitism has animated modern Zionism, while Arab and Muslim antisemitism is mentioned only as a logical result of Jewish ambition. Even the Mufti's antisemitism, which is well documented from his own writings and radio broadcasts, is downplayed as a response to Jewish power or realpolitik:
The figure of Haj Amin al-Husseini, grand mufti of Jerusalem, serves as an excellent indication of growing anti-Jewish sentiment during this period. A significant leader of the Palestinian Arabs, al-Husseini moved incrementally toward anti-Semitism as he opposed Jewish ambitions in the region. While he had economic dealings with the Jewish population, he also inspired and organized the growth of Arab paramilitary groups intent on thwarting the growth of Jewish power. When disputes over access to the holy places in Jerusalem led to open conflict in 1929, he proved unable to control his followers and ultimately gave assent to their actions.
...The grand mufti of Jerusalem gained notoriety for his active courting of the Axis powers. However, his motivations also involved significant anti-British sentiment, for he viewed the Germans as the likely victors in the war and sought to gain influence with them.
This is ahistorical but it reflects the general attitude of scholars towards Arab antisemitism: when it is mentioned at all, it is regarded as an unfortunate consequence of Jewish greed and power or an unintended result of other historical events. It is never considered on its own, and it is not mentioned as a continuation of centuries of Muslim attitudes towards Jews, as well as the influence of virulent Christian Arab antisemitism on Arab nationalism in the early 20th century which converted the Arab attitude towards Jews into full blown hate.
The bias is clear when we see the full-page entry on "Anti-Arab Attitudes and Discrimination:"
Anti-Arab attitudes, especially toward Muslim Arabs, as well as formal and informal policies and codes of conduct that unfairly target Arabs and are sometimes known as anti-Arabism have been especially virulent in Israel since 1948.
From reading this encyclopedia, one would believe that the only irrational hate in the conflict is that of Jews towards Arabs!