The concept of digital libraries is familiar to both librarians and library patrons today. These new libraries have broken the limits of space and distance by delivering information in various formats via the Internet. Since most digital libraries contain a colossal amount of information, it is critical to design more user-friendly interfaces to explore, understand, and manage their content. One important technique for designing such interfaces is information visualization. Although computer-aided information visualization is a relatively new research area, numerous visualization applications already exist in various fields today. Furthermore, many library professionals are also starting to realize that combining information visualization techniques and current library technologies, such as digital libraries, can help library users find information more effectively and efficiently. This article first discusses three major tasks that most visualization for digital libraries emphasize, and then introduces several current applications of information visualization for digital libraries.