This document provides an overview of semantic web technologies and their role in advancing digital library functions. It begins with definitions of semantic web, its main components like RDF, OWL and ontology. It then discusses functions of digital libraries like access to information, support for multimedia and advanced search. The key role of semantic web for digital libraries is described as representing various types of objects and relations between them to provide meaningful data that can be processed by computers. Technologies like XML, RDF and ontology help achieve this by annotating and describing data in a structured format. Finally, semantic web allows for improved resource sharing and networking across digital libraries by making data interoperable and extending its accessibility.