Ajaj Nuwahid was born in Lebanon in 1897, then moved to Syria. After the French took over Syria he decided to move to Jerusalem to fight against the British rule over Palestine and the Zionist movement. He was friends with the antisemitic Mufti of Jerusalem. He also had a role in having Jordan occupy and illegally annex the West Bank, because Palestinian Arab nationalism wasn't really what he was interested in after all. He then moved to Amman and then back to Lebanon in 1959.Since he lived in British Mandate Palestine in 1948, he was considered a "Palestinian refugee." However, since he moved back to his hometown, he might have successfully appealed to regain his Lebanese citizenship, as a number of "Palestinian refugees" managed to do in the 1950s.
His book about the Protocols of the Elders of Zion seems to have been more than just a translation, but indeed a full anti-semitic screed written in 1967 and expanding on the themes of the Russian forgery to apply them to modern Zionism. It has been through at least four editions.
The PA is praising, and claiming as one of their own, a full blown Jew-hater and inciter.
(h/t Ian)