For a number of reasons, CRL libraries have come to rely entirely on electronic delivery for many important scholarly source materials. Maintaining costly paper subscriptions to core science and humanities journals produced by Elsevier, Springer, and other publishers is now widely considered an unnecessary expense. And a growing number of libraries no longer subscribe to newspapers in paper or microform, and instead provide users access to electronic news aggregated by vendors like Factiva, ProQuest, and NewsBank.

CRL exists to ensure the long-term availability of critical research materials to member libraries. It has accomplished this by reliably maintaining and delivering newspapers, journals, books, dissertations, archives, and other materials that are not widely held. This strategy does not apply to born-digital research materials. To ensure access to electronic journals, news, and other born-digital content libraries must rely upon whatever archiving arrangements are put in place by producers, publishers, and aggregators. Libraries are often expected to bear the costs of such archiving provisions either directly, by subsidizing the creation and maintenance of digital repositories, or indirectly, through high subscription rates.

Since these costs are significant, due diligence on this front involves determining the extent to which a given repository or archiving arrangement is likely to ensure long-term accessibility of its content. To make such determinations library directors must consider several technical and non-technical factors.

In this issue of Focus we identify some of these factors and suggest questions library directors should ask when considering investing in digital preservation solutions. These factors derive in part from the draft Audit Checklist for the Certification of Trustworthy Digital Repositories developed by the Research Libraries Group and National Archives and Records Administration. They form the basis of our analysis of a number of digital repositories under the Andrew W. Mellon Foundation-funded CRL Auditing and Certification of Digital Archives project. (We also will test and evaluate specific technical aspects of the repositories.)

As part of the CRL project Robin Dale has profiled three of the digital repositories we are examining. The profile information, disclosed by the repository organizations, will eventually be augmented through on-site technical and operational audits of the repositories. This preliminary information, however, should afford CRL library directors some context for their own risk analysis.

Such analysis and information on digital repositories will enhance the ability of CRL libraries to ensure for their communities long-term access to critical knowledge, as they move with confidence and certainty to efficient forms of knowledge preservation and management.