This podcasts explore various approaches to managing access control in computer systems, prominently featuring Attribute-Based Access Control (ABAC) and Relationship-Based Access Control (ReBAC). They explain how ABAC grants access based on attributes of users, resources, and the environment, offering fine-grained control beyond traditional roles. The sources also discuss ReBAC, which determines access based on the relationships between users and resources, highlighting its use in social network systems and its ability to model contextual permissions. Furthermore, the texts introduce SpiceDB, an open-source database inspired by Google's Zanzibar system, designed for scalable and consistent storage and querying of authorization data for implementing fine-grained access control using models like ReBAC. Practical examples and considerations for implementing these models in different applications and at scale are also covered.