Report on a national programme to preserve the contents of millions of brittle books in the USA. The mechanical aspects of organizing a preservation project on this scale are complex, requiring sophisticated bibliographic and access structures. Microfilm will most likely be the medium of first choice, but newer technologies are also being considered. Long-term funding is sought. Related preservation issues will be addressed, such as the use of acid-free paper in bookmaking, mass deacidification, and special materials (e.g. Maps and music).