Schlager and Ostrom analyze the concept of property-rights regimes in relation to natural resources, emphasizing the confusion caused by the term "common-property resource," which can refer to government-owned, no-one-owned, or community-owned resources. They propose a conceptual framework distinguishing between different bundles of rights: authorized user, claimant, proprietor, and owner. This framework helps analyze how varying rights influence resource management and outcomes. The paper discusses operational and collective-choice levels of action, highlighting how rules and rights shape resource use. It defines access and withdrawal rights as key operational-level rights. Claimants have management rights but not exclusion or alienation. Proprietors have management and exclusion rights but not alienation. Owners have all rights, including alienation. The paper uses the Maine lobster industry as a case study, showing how de jure and de facto property rights coexist and interact. De jure rights are legally recognized, while de facto rights are self-enforced. The study finds that de facto proprietors often manage resources more effectively than de jure authorized users, as they have stronger incentives to invest in resource management. The paper also discusses the importance of exclusion rights in encouraging long-term investments and efficient resource use. It highlights the challenges of managing common-pool resources and the need for better understanding of the conditions that enhance or hinder the development of efficient property-rights regimes. The study concludes that effective property-rights systems are complex and require careful institutional design to ensure sustainable resource management.Schlager and Ostrom analyze the concept of property-rights regimes in relation to natural resources, emphasizing the confusion caused by the term "common-property resource," which can refer to government-owned, no-one-owned, or community-owned resources. They propose a conceptual framework distinguishing between different bundles of rights: authorized user, claimant, proprietor, and owner. This framework helps analyze how varying rights influence resource management and outcomes. The paper discusses operational and collective-choice levels of action, highlighting how rules and rights shape resource use. It defines access and withdrawal rights as key operational-level rights. Claimants have management rights but not exclusion or alienation. Proprietors have management and exclusion rights but not alienation. Owners have all rights, including alienation. The paper uses the Maine lobster industry as a case study, showing how de jure and de facto property rights coexist and interact. De jure rights are legally recognized, while de facto rights are self-enforced. The study finds that de facto proprietors often manage resources more effectively than de jure authorized users, as they have stronger incentives to invest in resource management. The paper also discusses the importance of exclusion rights in encouraging long-term investments and efficient resource use. It highlights the challenges of managing common-pool resources and the need for better understanding of the conditions that enhance or hinder the development of efficient property-rights regimes. The study concludes that effective property-rights systems are complex and require careful institutional design to ensure sustainable resource management.