Abdul Alhazred (sometimes called the "Mad Arab") is a fictional character created by the horror writer H. P. Lovecraft.
According to Lovecraft's "History of the Necronomicon"( written 1927, first published 1938), Alhazred was:
a mad poet of Sanaá, in Yemen, who is said to have flourished during the period of the Ommiade caliphs, circa 700 A.D. He visited the ruins of Babylon and the subterranean secrets of Memphis and spent ten years alone in the great southern desert of Arabia -- the Roba el Khaliyeh or "Empty Space" of the ancients -- and "Dahna" or "Crimson" desert of the modern Arabs, which is held to be inhabited by protective evil spirits and monsters of death. Of this desert many strange and unbelievable marvels are told by those who pretend to have penetrated it. In his last years Alhazred dwelt in Damascus.
In 730, while still living in Damascus, Alhazred reputedly authored in Arabic, a book of ultimate evil, "al Azif", which would later become known as the Necronomicon. Again according to Lovecraft:
Of his final death or disappearance (738 A.D.) many terrible and conflicting things are told. He is said by Ebn Khallikan (12th century biographer) to have been seized by an invisible monster in broad daylight and devoured horribly before a large number of fright-frozen witnesses. Of his madness many things are told. He claimed to have seen fabulous Irem, or City of Pillars, and to have found beneath the ruins of a certain nameless desert town the shocking annals and secrets of a race older than mankind. He was only an indifferent Moslem, worshipping unknown entities whom he called Yog-Sothoth and Cthulhu.
Those who have any dealings with the Necronomicon usually come to an unpleasant end, and Alhazred was no exception. August Derleth later placed the event on 731 instead.
Derleth further wrote on the final fate of Alhazred in his story "The Keeper of the Key", first published in May, 1951. In this story Dr. Laban Shrewsbury (a reccuring Derleth character), and his assistant at the time Naylan Colum discovered Alhazred's burial site. More specificaly they were heading a caravan from Salalah, Oman and crossed the border to Yemen. There they found the unexplored desert area the Necronomicon names as "Roba el Ehaliyeh" or "Roba el Khaliyeh". At the center of the area they discovered the Nameless City, a domain of Hastur. Shrewsbury, as an old agent of Hastur and devoted enemy of his half-brother Cthulhu, crossed its gates in search of Alhazred's burial site. He indeed found the gate of Alhazred's burial chamber and learned of his fate. Alhazred was kidnapped in Damascus and brought in the Nameless City, where he had earlier studied and learned some of Necronomicon's secrets. As punishment for his betrayal of their secrets, Alhazred was tortured. Then they blinded him and severed his tongue, and finally executed him. The entrance to the chamber warned against disturbing him. But Shrewbury proceeded in entering the chamber and opening the sarcophagus. Though only rugs, bones and dust were all that remained of Alhazred, the sarcophagus also contained an incomplete personal copy of the Necronomicon, written in the Arabic alphabet. Then Shrewsbury used Necromancy to recall Alhazred's spirit and ordered it to draw a map of the world as he knew it. After obtaining the map, which revealed the location of R'lyeh and other secret places, Shrewsbury finally let Alhazred return to his eternal rest.