Technology has revolutionized the concept of libraries. Networking and computing technologies have now become sufficiently advanced to support the design and deployment of large digital libraries which are capable of supporting the conventional end-user functions. Digital libraries are a natural extension of the evolution in which libraries have been involved for centuries. They represent a fundamental leap forward in the provision of services for, and partnership with, information communities. Because of the "digital" nature, information resources can be shared over the powerful network. With the innovative use of information technology and the integration of many tools and techniques developed thus far and in the foreseeable future, information provision can be more complete, faster, and broad-based. Digital Libraries can be accessed anywhere, any time, by anyone who needs them. Thus, the potential should be great. This article provides an overview of digital and other electronic information resources, their characteristics, growth and developments, and their impact on information access and use. It also deals with issues relevant to building digital library collections and systems. (Contains 1 table and 4 figures.)