This chapter focuses on whether any of four carefully selected contemporary theories of law—Michael Moore's theory, Joseph Raz's theory, Robert Alexy's theory, and Alf Ross's theory—have interesting implications for legal argumentation. I argue (1) that Moore's and Alexy's theories of law have interesting implications for the interpretation and application of the law; (2) that Raz's thesis has interesting implications both for the interpretation and application of the law and for legal argumentation more broadly conceived, namely, for the legitimacy of judicial decision-making; (3) that Ross's theory, interesting though it is, lacks interesting implications for legal argumentation more broadly conceived and thus for the interpretation and application of the law, too; and (4) that claims (1)–(3) suggest that other theories of law, too, may have interesting implications for legal argumentation.