Abstract. Antitrust refusal to deal, essential facility, and price squeeze claims, and the doctrines that accommodate such claims are analytically peculiar. First, the claims seek to establish duties to deal—mandates—even with competitors, while antitrust is designed to restrict anticompetitive collaborations, not to enforce cooperation. Second, the claims are strongly associated with fairness perceptions and at least implicitly stress competitive unfairness, whereas their primary justification is market efficiency. Third, both fairness and efficiency may be desirable goals for public policies, but antitrust laws do not offer a regulatory framework to advance such goals through duties to deal. Forth, the claims and judicial rules that accommodate them have the intuitive appeal of rules of thumb, but they are too simplistic to address many common economic settings. This Chapter offers a general framework for the analysis of refusal to deal, essential facility, and price squeeze claims, or more broadly, alleged antitrust duties to deal.