Abdul Alhazred was the author of the Necronomicon.
the Necronomicon was the fictional invention of H. P. Lovecraft and many hoax Necronomicons have been published since his time. Lovecraft encouraged writers in his circle to borrow ideas like the Necronomicon for their own works to create a sense of verisimilitude. Other fictional Cthulhu Mythos tomes created by his fellow writers have also appeared in Doctor Who.