In all these cases, the arguments against the sales were more or less the same. They include: the legal and moral right of the vendors to sell the material; the issue of consultation with interested parties; the intrinsic importance of the books that are being sold and their significance within historic collections; and the question of how any funds resulting from the sale will be used. Strangely enough, in several of these cases the vendors of the books do not seem to have thought through the implications of what they were proposing to do or to have had detailed policies about disposing of books or about how best to use the money their sale might bring. The reputational damage that can come from selling what has been entrusted to their care seems obvious to most people, but apparently passes by some librarians and trustees of libraries. Who would give rare books to a library-or money with which to buy them-if they knew that the library was likely to sell them within a few years? The more opposition there is to a sale, especially one at auction, the less enthusiasm buyers have to put their money into acquiring books that come with a tainted or unhappy provenance. Books ripped untimely from their institutional homes are not as attractive as those that have long histories of being bought and sold by private collectors. Consequently, they tend to go for lower prices than they are expected to fetch. The funds libraries have raised from such sales have not always been spent successfully and, in at least one case, were not in the end spent at all or not for many years.

An appeal to the Charity Commissioners can provide a way round some of the historic terms of bequests, although "permanently" in the case of the Sterling bequest seems pretty clear to most people. But the other question of the right of temporary custodians to sell what was intended always to be part of a collection or an institution is more complicated. Librarians, trustees and even the Charity Commissioners come and go and are subject to occasional rushes of blood to the head; institutions have longer and more permanent existences. They exist to preserve material and to serve the academic and the larger community; it might be thought that those who are most interested professionally in that material and perhaps know most about it should be asked for their views concerning the prospect of it being sold. But this rarely happens; such consultations are often of a highly selective kind and the results fudged.

What is perhaps strangest about these sorts of sales from libraries is that librarians and those involved in the decision to dispose of material often know very little about the material that they are proposing to sell. At the time of the Rylands sale, I vividly remember C.B. (Brian) Cox (1928-2008),  Professor of English at Manchester University and Pro-Vice Chancellor, closely involved in the sale, saying how interesting it was to learn about the significance of the "duplicates" that the library was selling, even as the auctioneer's hammer was descending on the collection. Senate House Libraries also believed that the four Shakespeare Folios were "duplicates" or "essentially duplicates" of books they already owned. Despite a century and more of the painstaking investigation of books printed before 1800 on the hand-press, it is surprising to have to explain to professional librarians and others that there is no such thing as a "duplicate" of this kind. Bibliographical investigation, on both sides of the Atlantic, has shown that as books passed through the press corrections, large and small, were made to their texts by printers and proof-readers. Rather than abandon the uncorrected pages or formes (one side of a sheet), they were bound promiscuously together so that, in theory, no two copies of the same edition are identical. Bibliographers and editors collate multiple examples of what most people would (wrongly) think of as identical copies to find these press variants. At the Folger Shakespeare Library in Washington D.C., Charlton Hinman collated 50 or so copies of the First Folio; the results of his research were at first glance disappointing, for the press variants he discovered were not as interesting or important as those found in, say, the first printing of King Lear. However, his eye-wrenching work on a machine of his own devising, which superimposed images of pages from two copies and flashed a light through them, allowed him eventually to recover the printing history of the most important witness to Shakespeare's plays and so to advance knowledge of how they were put into print.

Furthermore, each copy of an early printed book-or for that matter a more modern one-has its own distinctive history. Book historians are interested in who owned it, who read it, who wrote in it, to what uses it was put, how it was bought and sold. They will also want to pay particular attention to its binding, whether it is of the smart morocco kind, like the ones on the Sterling Folios, or cheaper and more every-day ones. Nor do copies of books simply exist in a vacuum: they relate to other items collected by the same person and to larger institutional holdings. The Dr Williams First Folio had been in the Library since at least 1729-like a front tooth knocked out of someone's mouth, it is not there any more. Books from the hand-press period are not "duplicates" and the more we learn about them, the more their unique individuality becomes apparent. In the last few years, scholars have been paying increased attention to what the paper used in the production of early printed books can reveal: it turns out to be a great deal. Investigation of the paper that can be found in the First Folio is still in its early stages and is likely to reveal that stocks appear in different configurations in different copies. Were the Sterling First Folio to be sold, it would be most likely to be bought by an individual collector or a corporate investor in the US or the Far East (hence the proposed tours to those areas) and removed from sight; one more copy for investigation would be removed from public access in a capital city. The research potential and significance of these books is, therefore, enormous for our knowledge of the 17th-century book trade and for understanding the history of Shakespeare's texts. Strangely enough, although we know a great deal about the First Folio, research into its three successors is quite underdeveloped and there is still much to be found out about them.