are arranged by the aid of "headings," which are selected in accordance with various systems of rules.
II. The Subject-Catalogue, where the books are arranged according to arbitrary divisions and subdivisions of human knowledge, or under an alphabetical series of headings derived from those portions of human knowledge to which the respective books claim to contribute.
III. The Shelf-Catalogue, in which the titles of the books follow the same order as the actual volumes on the shelves.
IV. A fourth, the Form-Catalogue, is designed to classify books according to the forms in which they present thought (e.g. novels, biographies, tales, essays, &c.). It is little used by itself, but enters into combination with I. and II., sometimes without the compilers' intention.
V. A fifth, the Dictionary-Catalogue, is a combination of I., II., and IV.
I. AUTHOR-CATALOGUE
The author-catalogue first claims our attention, as being absolutely indispensable, both to the reading public and the staff of any library existing for serious purposes. The largest compilations of the kind available for public use are those of the British Museum Library and the Bibliothèque Nationale at Paris, but of the latter only one volume, containing books of known authorship in the first half of letter A, has as yet been published (1897). The Museum catalogue, therefore, takes precedence by seniority and completeness.
