Calabresi and Melamed propose a legal framework that integrates property and tort law to analyze legal relationships. They argue that this integrated approach can help solve issues like pollution and criminal sanctions. The framework focuses on "entitlements," which are protected by property, liability, or inalienability rules. The first issue in any legal system is determining who is entitled to prevail in conflicts. The state must decide which party should be favored, as without such a decision, "might makes right" would prevail. Once an entitlement is decided, the state must enforce it, which often requires intervention. The state must also decide how to protect entitlements and whether they can be sold or traded. The article considers three types of entitlements: those protected by property rules, liability rules, and inalienability rules. Property rules involve voluntary transactions, liability rules involve state-determined values, and inalienability rules prohibit the sale of entitlements. The article argues that most entitlements are mixed, and the choice of rules depends on the circumstances. The article also discusses economic efficiency, distributional goals, and other justice reasons for setting entitlements. It argues that economic efficiency is not the sole reason for choosing entitlements, as distributional preferences and other justice considerations also play a role. The article concludes that inalienability rules are different from property and liability rules, as they not only protect entitlements but also limit or regulate their grant. The article also discusses the use of liability rules in situations where market valuation is inefficient or too costly. It argues that inalienability rules may be appropriate in cases involving external costs, moralisms, self-paternalism, and true paternalism. The article concludes that the framework can be applied to pollution control, where the choice of rules depends on the circumstances.Calabresi and Melamed propose a legal framework that integrates property and tort law to analyze legal relationships. They argue that this integrated approach can help solve issues like pollution and criminal sanctions. The framework focuses on "entitlements," which are protected by property, liability, or inalienability rules. The first issue in any legal system is determining who is entitled to prevail in conflicts. The state must decide which party should be favored, as without such a decision, "might makes right" would prevail. Once an entitlement is decided, the state must enforce it, which often requires intervention. The state must also decide how to protect entitlements and whether they can be sold or traded. The article considers three types of entitlements: those protected by property rules, liability rules, and inalienability rules. Property rules involve voluntary transactions, liability rules involve state-determined values, and inalienability rules prohibit the sale of entitlements. The article argues that most entitlements are mixed, and the choice of rules depends on the circumstances. The article also discusses economic efficiency, distributional goals, and other justice reasons for setting entitlements. It argues that economic efficiency is not the sole reason for choosing entitlements, as distributional preferences and other justice considerations also play a role. The article concludes that inalienability rules are different from property and liability rules, as they not only protect entitlements but also limit or regulate their grant. The article also discusses the use of liability rules in situations where market valuation is inefficient or too costly. It argues that inalienability rules may be appropriate in cases involving external costs, moralisms, self-paternalism, and true paternalism. The article concludes that the framework can be applied to pollution control, where the choice of rules depends on the circumstances.