A reader about to venture into a thick reference work (especially one dealing with theology) has the right to ask for additional mercy from its editor: that is, that the editor specifies the aim and use of the work. A few glosses about the title will answer this request. First and foremost, this is an encyclopedia of theology, meaning, in a restrictive sense that is also a precise sense, the massive amount of discourse and doctrines that Christianity has assembled about God and its experience of God. There are other discourses on God, and theology was often the first to champion their rationality. By selecting one term to refer to one practice (historically circumscribed) of the logos and one call (historically circumscribed) in the name of God, we do not pretend to deny the existence or the rationality of other practices or calls-we are only offering to make use of theological to name the fruits of a kind of covenant between the Greek logos and the Christian restructuring of the Jewish experience. When the philosopher discusses God, it rarely appears that his interest is theological, in the fixed sense of the term. Because Judaism was able to tie in the richest things it had to say without pillaging the theoretical legacy of classical antiquity, it is also unlikely that theological needs to be applied to its doctrines. Likewise, because the Islamic Kalam itself follows some rather original structuration rules, it is inadequate to baptize it “Islamic theology,” unless one accepts a certain vagueness. As for the rigorous comparative study of all the discourses in which the signifier God (whether its intervention be that of name, concept, or other) appears, it is still in its infancy.