[...] In the early Middle Ages, the problem was the lack of books, its scarcity, to the sixteenth century [After the invention of printing], its superfluity. Already in 1550 an Italian writer complained that he had "so many books that do not even have time to read the titles." The books were a forest in which, according to the reformist Italo Calvino (1509-1564), readers might be lost. It was an ocean in which readers had to sail, or a stream of written material that was hard not to drown.

As the books were multiplied, the libraries had to be getting bigger. And with increasing the size of libraries, it became more difficult to find a specific book on the shelves, so they started to be necessary in the catalogs. Those who concocted the catalogs had to decide if ordered by topic or by alphabetical order of authors. Since the mid-sixteenth century, printed bibliographies offered information about what was written, but as these became more voluminous compilations, it was increasingly necessary in the literature by topic.

Librarians are also faced problems of maintaining catalogs a day and keep abreast of new publicaicones. Specialized magazines to provide information about new books, but also you check the amount of these multiplied, it became necessary to find another place information about them. Since there were many more books than you could read in a lifetime, readers need the help of selected bibliographies to discriminate between them and, from the late seventeenth century, reviews of new publications. [...]

BRIGGS, Asa; BURKE, Peter. From Gutenberg to the Internet: A social history of the media. Madrid: Taurus, 2005. P. 30 to 31