Printed Books to 1640 JULIAN ROBERTS

BIBLIOGRAPHY IS A TECHNIQUE PROPER to librarians. There are many outstanding exceptions to this resoundingly simple statement, but it nevertheless remains true that the librarian is the principal interpreter and beneficiary of the evidence which books, through their physical features, offer about themselves. One of the librarian's most elementary acts, that of cataloging, is bibliographical in nature, in that it records without comment or explanation, certain evidence offered by the book concerning itself, which must be sufficient to differentiate it from other books. To take an example, if one catalogs a book called The Shield of Achilles published in 1955, such information is only sufficient to differentiate this compilation from other books by the same author, and from other books which have on their title pages, "The Shield of Achilles, Second edition, 1962" and so on. The information recorded fails to reveal that the book is not about the Trojan War or ancient armor. The trends to be considered in this article are given fundamental unity by the fact that they all arise from attempts to interpret and use knowledge derived from the differentiation of books by means of their physical characteristics. It is this differentiation which gives unity to the subject called bibliography (historical or analytical bibliography, that is, as opposed to subject "bibliography," the listing of books and articles by their subjects). The various uses made of this knowledge range in complexity from the distinguishing of books, editions, and perhaps issues, which is necessary for the compilation of union and short title catalogs, to the microscopic precision of Charlton Hinman's collation of the copies of the First Folio of Shakespeare in the Folger Library. No survey of bibliographical trends can afford to omit work done at either end of this spectrum, and the present consideration will follow the pattern of increasing complexity; the information derived from bibliography varies with the sophistication of its method. A point