Lightweight Directory Access Protocol (LDAP) is a fast-growing technology for accessing common directory information. LDAP has been embraced and implemented in most network-oriented middleware. As an open, vendor-neutral standard, LDAP provides an extendable architecture for centralized storage and management of information that needs to be available for today"s distributed systems and services. After a fast start, it can be assumed that LDAP has become the de facto access method for directory information, much the same as the Domain Name System (DNS) is used for IP address look-up on almost any system on an intranet and on the Internet. LDAP is currently supported in most network operating systems, groupware and even shrink-wrapped network applications. This redbook was written for those readers who need to understand the basic principles and concepts of LDAP. Some background knowledge about heterogeneous, distributed systems is assumed and is highly beneficial when reading this book. Because this book is not meant to be an LDAP implementation guide, it does not contain product-related or vendor-specific information other than that used in examples.