Directories: Managing Data for Networked Applications. Divesh Srivastava. Directories have recently emerged as an essential component of the network infrastructure, and are being used to store a wide variety of information to support network applications. These include address books for messaging applications, user preferences for configuration management, access control lists and certificates for security applications, and profiles and policies in the DEN (directory enabled networks) initiative. Network directory data is typically heterogeneous, highly distributed and replicated, requiring autonomy across multiple directory servers while allowing for conceptual unity, in a way that is not well supported by conventional relational or object-oriented databases. Efficient management of such data creates new challenges and exciting opportunities for the database community. In late 1997, LDAPv3 (Lightweight Directory Access Protocol, version 3) was approved as a proposed IETF standard for modeling and querying directory information, as well as accessing directory services over the Internet. A large number of LDAP directory products are now available from vendors such as Oracle, Novell, AOL (Netscape), IBM, and Innosoft, and a variety of non-LDAP directories provide LDAP interfaces. This tutorial describes key features of LDAP directories, and presents recent research inspired by LDAP directories. Its intended audience includes researchers in databases and/or network systems, software and application developers, and the LDAP community.