After a brief summary of Duns Scotus’ life and works, this chapter offers an overview of Scotus’ theology, showing how Scotus’ principal theological aim was theoretical generality: the attempt to treat of God and creatures using the same metaphysical tools—in particular, the same theories of unity and distinction. Despite his status as a radically innovative and original thinker, Scotus’ debt to twelfth-century theology is also highlighted, along with the aim, shared with these earlier theologians, of showing as much as possible of the Christian faith without appeal to revelation. Topics covered include: the theory of individuation, the coherence of the doctrine of the Trinity, the proof for the existence of God as a Trinity of persons, the univocity of being, the Immaculate Conception, Christocentrism, will and freedom, and the doctrine of grace.