Over the course of almost twenty years of field work, we have received enormous help from the Library community in Europe and North America. We have worked in over 500 different collections, from the greatest university and national libraries to small municipal and private collections. Almost all have books of great rarity.The publication of the USTC as a free-access on-line resource provides the opportunity to develop our relationship with libraries in different ways.

Over the years, keepers of rare and early printed books have been extremely indulgent of our efforts. They have opened their reading rooms during closed periods, and delivered far beyond their normal daily quotas of books (one library told us they had fetched us as many books in a three week trip as they normally deliver to readers in twenty five years). We hope this resource will express our appreciation of their efforts, and begin to repay their consideration.

Rarity and Value

One of the great peculiarities of the history of early printed books is that the most precious items are seldom the rarest. The large, illustrated volumes most valued by collectors often survive in remarkably large numbers: precisely because they were highly valued when they were first published, and quickly made their way into libraries and other secure locations. Almost a third of the original print run of Gutenberg?s Bible can be located today almost five hundred years later.The common experience of more mundane books was very different. Many small books published in editions of a thousand or more survive in only a single copy – many have disappeared altogether. Until the publication of the USTC it was virtually impossible for libraries to know which are their rarest books: often they were small pamphlets or broadsheets bound into a volume with other items, and not always catalogued separately. In 2010 the project identified, and surveyed, a single volume containing 200 Netherlandish items previously catalogued under a collective title. All turn out to be unique and previously unknown. This volume was not even stored among the library?s reserve items. All in all, perhaps as many as 40% of the items listed in the USTC can be linked to only one known surviving copy.

Conservation Priorities

These rarest items, however humble, should be a high priority for conservation. Many libraries now undertake their own programmes of digitisation and they will want to know which of their books are the rarest. The USTC group can, on request, supply libraries with lists of their books which we believe to be the unique surviving copy. We could also tell them, for instance, which are the only copy known in their own locality, state or country. This will be an invaluable service for libraries competing for scarce resources to preserve their cultural heritage.

Digitisation

The last decade has seen a substantial effort to make early printed books available in full text digital copies. Libraries deciding which of their books to digitise will not always know when copies of these same editions have been made elsewhere: to establish this requires multiple searches which would not always find the way to books on libraries? own web-sites.By flagging clearly for which books digital copies are available the USTC will assist libraries in deciding where they should prioritise their own efforts. It is to be expected that the next ten years will see considerable progress in completing the coverage of digital texts of almost all known early printed books.

Improving Records

With the publication of the USTC we enter a much more intensive period of dialogue with libraries, archives and users. Many librarians will want to offer improvements, additions and corrections to our records: sometimes these will refer to items mis-identified in their published catalogues or mis-keyed during retro-conversion. On other occasions they will want to signal the existence of other copies that we have not listed. This can be achieved through our feedback loop on the USTC. The publication of the USTC may also help librarians to argue for making it a priority to address the many thousands of un-catalogued early printed books that still exist in many collections.

Web-based Exhibitions

All public institutions are under pressure to increase footfall, while protecting precious and rare materials from inappropriate use. The web-based exhibition, of the sort staged to accompany the launch of the USTC, offers an opportunity to achieve these objectives in a safe environment. The web allows holding institutions to co-operate to bring together a coherent body of material that will never be seen, or used, together in any other way.

New Scholarship

This capacity to compare and evaluate printed items in widely dispersed collections should also greatly assist scholars involved in the study of early printed books. Physical and technical bibliography depends on the close examination of works that are often extremely rare, and are usually scattered between many different collections. With the USTC scholars will now be able to assemble a corpus and strategize their research priorities much more effectively.