The Necronomicon is one of those things which has aquired something of an occult following, and with it, it is cloaked in falsehood and misunderstanding, and today is comonly mistaknely beleived to be a book of sorcery, and a sort of grimoire, though this is quite far from the truth. It was the famed occult writer H.P. Lovecraft, whom is largely responseable of the mistaken idendity of this text.
So just what is the Necronomicon?
Its name litteraly translates to Book of Dead names, and it was orignaly concived by Alhazred asa history, and hence "a book of things now dead and gone". An alternative derivation of the word Necronomicon gives as its meaning "the book of the customs of the dead", but again this is consistent with the book's original conception as a history, not as a work of necromancy.
The author of the book shared with Madame Blavatsky a magpie-like tendency to garner and stitch together fact, rumour, speculation, and complete balderdash, and the result is a vast and almost unreadable compendium of near-nonsense which bears more than a superficial resemblance to Blavatsky's
The Secret Doctrine.
In times past the book has been referred to guardedly as Al Azif , and also The Book of the Arab. Azif is a word the Arabs use to refer to nocturnal insects, but it is also a reference to the howling of demons (Djinn).
The Necronomicon was written in seven volumes, and runs to over 900 pages in the Latin edition.
The book is best known for its antediluvian speculations. Alhazred appears to have had access to many sources now lost, and events which are only hinted at in Genesis or the apocryphal Book of Enoch, or disguised as mythology in other sources, are explored in great detail. Alhazred may have used dubious magical techniques to clarify the past, but he also shared with the 5th. century B.C. Greek writers such as Thucydides a critical mind, and a willingness to explore the meanings of mythological and sacred stories. His speculations are remarkably modern, and this may account for his current popularity. He believed that many species besides the human race had inhabited the Earth, and that much knowledge was passed to mankind in encounters with beings from "beyond the spheres" or from "other spheres". He shared with some Neoplatonists the belief that the stars are similar to our sun, and have their own unseen planets with their own lifeforms, but elaborated this belief with a good deal of metaphysical speculation in which these beings were part of a cosmic hierarchy of spiritual evolution. He was also convinced that he had contacted beings he called the "Old Ones" using magical invocations, and warned of terrible powers waiting to return to re-claim the Earth. He interpreted this belief (most surprisingly!) in the light of the Apocalypse of St. John, but reversed the ending so that the Beast triumphs after a great war in which the earth is laid waste.
http://www.digital-brilliance.com/necron/necron.htm#What