Use of the Extensible Markup Language (XML) has the potential to exceed the impact of MARC on librarianship. While MARC is limited to bibliographic description, XML provides a framework for encoding anything from a bibliographic record for a book to the entire book itself. XML is quickly becoming the standard method by which information of a variety of sources is encoded, transported and processed. Find out how your library can benefit. Here are actual examples of how libraries are using XML to solve problems, expand services and improve systems. Areas covered include integrated library systems, interlibrary loan, cataloguing and indexing, building collections, databases, data migration and systems interoperability.