The Library of Congress National Digital Library Program (NDLP) is assembling a digital library of reproductions of primary source materials to support the study of the history and culture of the United States. Begun in 1995 after a five-year pilot project, the program began digitizing selected collections of Library of Congress archival materials that chronicle the nation's rich cultural heritage. In order to reproduce collections of books, pamphlets, motion pictures, manuscripts and sound recordings, the Library has created a wide array of digital entities: bitonal document images, grayscale and color pictorial images, digital video and audio, and searchable e-texts. To provide access to the reproductions, the project developed a range of descriptive elements: bibliographic records, finding aids, and introductory texts and programs, as well as indexing the full texts for certain types of content.