This article is the first of a series, and the precursor of a monograph on Ibn al-Muqaffa c ’s work. I give here a short description of the period of his times, those times of ferment in which Arabo-Islamic civilisation was first formed, and then continue with a more detailed analysis of what is probably the most controversial work attributed to him. I set out to prove that this “Manichean Apology” — which is in fact a “Rationalist Critique of Islam” — is very probably authentic, and gives an insight into the ontological foundations of Ibn al-Muqaffa c ’s ethical and political system. The article concludes with a summary of his philosophy as it can be reconstructed from his works.