Microsoft Active Directory is a directory service developed by Microsoft for Windows domain networks. It is used for managing computers and other devices on a network, allowing administrators to create and manage user accounts, groups, and permissions. This centralized management helps ensure security and organization within an enterprise. Active Directory also supports various services, such as Group Policy, which allows administrators to enforce specific configurations and settings across multiple devices. Additionally, it provides authentication services, enabling users to log in securely and access resources based on their roles and permissions within the organization.