This chapter frames Hobbes’s ethics against the background of the history of ethics, on the one hand, and recent work on normativity and reasons, on the other. On the ancient Greek conception of ethics, all practical reasons derive from one’s own ultimate good. The modern conception, by contrast, took the form of a juridical code of laws and obligations that in principle could conflict with one’s own good. The basis for this shift had been laid by classical natural-law theory, rooted in the Stoics, Cicero, and Aquinas. But the decisive break occurred with the emergence of an intrinsically normative and juridical notion of obligation in Grotius and Hobbes—juridical in that the obligation is owed to others with standing to hold one accountable. Hobbes transformed obligation and natural law by taking the radical step of severing obligation from natural sociability and juridical obligation from natural law. He was also at the forefront of attempts to reconcile ethics with the emerging mechanistic sciences. This chapter establishes the book’s conceptual framework by showing how contemporary distinctions between normative, explanatory, and motivational reasons, reasoning, rationality as a source of precepts, and the balance of normative reasons map onto Hobbes’s vocabulary and thought.