Before the invention of printing, when copies of a book were few, it was common to find works falsely attributed to an author. The person of unorthodox opinions, like the PseudoDionysius, assigned his works to someone of unimpeachable reputation in order to avoid censorship or other obstacles to circulation. Or a man might insert heretical material into a rival's book to discredit him. Of al-Ghazali's Maḍnūn (? aṣ-Ṣaghīr), D. B. Macdonald wrote: —

“Of course it is quite possible and in accordance with the rules of Muslim polemic that there should also have been in circulation a false Maḍnūn teaching these heretical doctrines. Many such cases occur. A book against the belief in saints was ascribed to Abū Bakr ar-Rāzī (d. cir. 290–320) … and, it was suspected, falsely, in order to bring him into discredit. The same thing happened to ash-Sha'rānī. One of his enemies obtained a copy of his Al-Baḥr al-Mawrūd, left out parts and inserted others of a heretical nature, and then spread it as the original work. In defence ash-Sha'rānī was compelled to lay before the ‘Ulamā’ of Cairo his original copy signed by themselves, and so demonstrate the spuriousness of the other. Again, ash-Sha'rānī had to defend Ibn al-'Arabī against a similar injury. Some hostile theologians interpolated his Futūḥāt with heresy. Even Fakhrad-Din ar-Rāzī suffered from this; and there were enough suchcases for ‘Alī b. Muḥammad al-Miṣrī to make up a list of them. So we need not be at all surprised if this befell al-Ghazālī also …”