The Islamic culture centered in medieval Baghdad was one of the first to adopt and transform pagan Greek philosophy. Where does the discussion of the one God fall within the curriculum of sciences as understood by the Arabic philosophers? What is the subject of metaphysics, also called “theology” or “first philosophy,” and what is its relationship to God? Contemporary Aristotelian scholarship is divided on what first philosophy for Aristotle is really about: god or being qua being? al-Kindī, the “philosopher of the Arabs,” is usually thought to identify first philosophy with the science of the First Cause. In contrast, al-Fārābī is often presented as opposing al-Kindī’s theological understanding of metaphysics and as turning it into something secular: ontology. The chapter locates the problem against the background of the contemporary discussion of Aristotle and the Greek commentators. It then becomes clear that al-Fārābī is the first thinker to explain how the discussion of the First Cause and of being necessarily belongs to one and the same science. His explanation in On the Aims of Aristotle’s Metaphysics was developed by Avicenna, held by Aquinas and Duns Scotus, and became the mainstream view in European philosophy, a view still detectable in Kant. I lay out the argument of al-Fārābī’s Aims in stages. Doing so leads to a new interpretation of the “Second Teacher” on the aim of metaphysics: in a word, if one sets aside the Heideggerian implications, the aim is onto-theological. An analysis of al-Kindī’s works discloses that, even if al-Fārābī’s magisterial solution was prompted by al-Kindī’s imprecision, the two philosophers are not in fundamental disharmony. The result is a new account of the history of metaphysics as it was transformed in early Arabic philosophy.