User directories are organized collections of information about users within a system or network. They typically include details such as usernames, passwords, contact information, and user roles. User directories help manage access to resources and services, ensuring that only authorized individuals can access specific data or applications. These directories can be found in various environments, including operating systems, web applications, and corporate networks. They often utilize protocols like LDAP (Lightweight Directory Access Protocol) to facilitate communication and data retrieval. User directories play a crucial role in maintaining security and streamlining user management processes.