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 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.
The reproductions were produced with a variety of tools: scanners, digital cameras, devices that digitize audio and video, and human labor for rekeying and encoding texts. American Memory employs national-standard and well established industry-standard formats for many digital reproductions, e.g., texts encoded with Standard Generalized Markup Language (SGML) and images stored in Tagged Image File Format (TIFF) files or compressed with the Joint Photographic Experts Group (JPEG) algorithm. In other cases, the lack of well established standards has led to the use of emerging formats, e.g., RealAudio (for audio), Quicktime (for moving images), and MrSid (for maps). Technical information by types of material and by individual collections is also available at this site.
A physical library is more than a catalog that points to volumes on shelves. A digital library is more than a database, and the future National Digital Library will be much more than a universal union catalog. We envision the National Digital Library as a set of distributed repositories of managed content and a set of interfaces (some of which will resemble traditional catalogs) to that content. Some interfaces may offer comprehensive access to the entire resource, while others will be specialized by content, by intended audience, or by primary purpose. Some interfaces will be closely tied to a particular repository, while others will provide access to a selection of content from distributed repositories.
Access to the content in the National Digital Library will not be limited to searching a bibliographic database. Even in traditional libraries, users do not start every visit by searching the catalog. Instead, library patrons browse current issues of favorite journals or lists of new acquisitions, use specialized indexes to journal literature, or consult bibliographies, references from scholarly publications, and lists of readings. The digital library must be usable in equivalent ways. School teachers who use the online collections at the Library of Congress have already communicated their eagerness to find shortcuts to the most valuable materials so that they can quickly illustrate classroom presentations or develop lesson plans.
From the user’s point of view, the digital library has the potential, in ways not yet realized and not possible with traditional library resources, to be an extension to every desktop, classroom, and personal library. Patterns of use of the World Wide Web already demonstrate that teachers, scholars, and students will want to refer to items in the digital realm as active links from reading lists, articles, textbooks, and term papers. We also know that students will want to work with these items in their own electronic environments, constructing presentations, reports, and online projects.
Digital Library Users
In 1989, to help launch the American Memory pilot project, a consultant surveyed 101 members of the Association of Research Libraries and the 51 state library agencies. The survey disclosed a genuine appetite for on-line collections, especially in research libraries serving higher education. The American Memory pilot (1990-1995) identified multiple audiences for digital collections in a special survey, an end-user evaluation and in thousands of conversations, letters and encounters with visitors.
The most thorough audience appraisal carried out by the Library of Congress consisted of an end-user evaluation conducted in 1992-1993. Forty-four school, college and university, and state and public libraries were provided with a dozen American Memory collections on CD-ROMs and videodisks. (These formats are no longer being supported.) Participating library staff, teachers, students and the public were polled about which digitized materials they had used and how well the delivery systems worked. The evaluation indicated continued interest by institutions of higher education as well as public libraries. The surprising finding, however, was the strong showing of enthusiasm in schools, especially at the secondary level.
The evaluation team learned that recent reforms in education had created a need for primary-source historical materials such as those in the Library’s incomparable collections. Teachers welcomed digitized collections to aid in the development of critical thinking skills; school librarians used the electronic resource to inculcate research skills. These findings have been validated in the educational outreach program initiated by the Library of Congress in 1995 and initially funded by the Kellogg Foundation.
In 1995, in conjunction with the launch of the Library of Congress National Digital Library Program, the Library brought together leading history and social studies K-12 teachers and librarians to consider how archival on-line resources could best be used in the nation’s schools. The participants at this Educator’s Forum validated earlier findings: that while the primary sources were in great demand, for teachers to be able to make effective use of them, they needed additional materials to frame the collections and the topics represented in the collections. To this end in 1996, the Library of Congress developed The Learning Page