Present Tendency.—Many schemes have been devised for the classification of books, some very simple, others extremely elaborate. The present tendency is to adopt the more elaborate classification. Formerly most libraries were not classified at all, but the books were arranged in the order in which they were received, the only grouping of the books being in such cases one based on size,—folios in one place, quartos in another, in order to save shelf room. Assuming that the books in the library were numbered according to the date of their accession from one up to, say, twenty thousand, it is clear that the reader could find a book by a particular writer quickly enough by looking up its number in the catalog, but if he had wished to consult thirty books on one subject, it would be a very tedious operation and most readers would not take the time for it.
Simple forms of Classification.—The most common plan in English libraries is a modification of this scheme. The books are divided into about ten classes and the books in each class are arranged in the order in which they are received. The classes are distinguished by capital letters. An example said to be very common in England, is as follows.
A. Theology and philosophy.
B. History and biography.
C. Travel and topography.
D. Law, politics, commerce.
E. Arts and sciences.
F. Fiction.
G. Philology.
H. Poetry and drama.