I have said, under the heading 'Classification,' that it is not advisable or necessary to attempt any rigid classification upon the shelves. One good reason for this is that by so doing you are trying to do what can so much better be done by a catalogue. No one who uses books very much but sooner or later becomes grateful for the existence of an alphabet and an arrangement by A B C. Carlyle once said, 'A library is not worth anything without a catalogue; it is a Polyphemus without any eye in his head, and you must confront the difficulties, whatever they may be, of making proper catalogues.'

'The classification of Pepys' library was to be found in the catalogues, and as Pepys increased in substance he employed experts to do this work for him.'[37]

No catalogue is of any use unless you can tell from it (1) All that the library possesses of the known books of a known author at one view, as well as (2) All that it possesses, by whomsoever written, on a known and definite subject.

The old catalogues were mostly very bad. Old methods have now given way to newer and better bibliographical systems, and, to take the case of a large country house, where books are scattered about in many rooms, a catalogue is most essential. The catalogue should, in most cases, be in MS., and not typewritten. Such an arrangement admits of additions being made more easily. The printed catalogue is adopted where the library is of special value, or if it has any particular class of books predominating to make it of use as a bibliography of a special subject. Lord Crawford's sectional catalogues of his library, already referred to, are the most valuable lists I know of for student purposes, but I believe very few people have ever seen them.

The catalogue of Lord Crawford's Proclamations, at Haigh Hall, is a marvel of industry and accuracy. Mr. Locker Lampson's Rowfant Library was catalogued, and the catalogue printed and sold, because it had special value as a collection of Elizabethan poetry. Mr. Edmund Gosse's Library catalogue was printed because it contained special collections of seventeenth-century literature. Whether the library be a student's library or a general library, a catalogue is essential. Gibbon had a catalogue of his books. I have seen so many amateur attempts at cataloguing private libraries that I am bound to say I do not think the plan of cataloguing one's own books in any way answers. Any catalogue may be better than no catalogue, but, if a catalogue is to be done, it is better by far to call in the assistance of some one whose work it is. It frequently happens that a family inherits a large library, and the inheritors, not having formed the collection, naturally can know but little, if anything, of its contents. Now, in such a case, and in many other cases, the best plan is to have your books overhauled, sifted, certain volumes weeded out, if necessary, others rebound, and the whole remainder carefully catalogued and described, the cases being numbered and the shelves lettered.

Very often the owner of a library sets out to catalogue his or her own books, and makes the initial mistake of entering them one by one in a MS. volume already bound up. Such a plan must end in failure and disorder, because it is impossible by this means to get the titles strictly alphabetical. Others I have seen commence writing the titles from the backs of the books. Other difficulties which are encountered are with anonymous books, and with such authors as used pseudonyms, and, in some cases, many pseudonyms. Such was Henri Beyle, whose books bear various disguises, such as De Stendhal, Cotonet, Salviati, Viscontini, Birkbeck, Strombeck, CÉsar Alexandre Bombet. The British Museum Library has ninety-one rules of cataloguing, forming, perhaps, the best cataloguing code in the world; but for private libraries such elaboration and detail is not necessary. The following are the main rules to be adopted in private libraries:—[38]

1. The catalogue should be arranged in one general alphabet, this being the most useful and the readiest form for reference. To render it, as nearly as possible, a correct representation of the contents of the library, each work has but one principal descriptive entry. The shelfmark is confined to this entry—duplicate shelfmark references, when the position of books is likely to be often altered, from the accession of additions to the library, &c., leading to frequent and unavoidable errors.

2. This entry is under the author's name when given on the title-page, or otherwise known, as being the only arrangement which allows one general rule to be followed throughout the catalogue.

3. Anonymous works, whose authors' names are unknown, are placed under the subjects to which they relate.

4. Cross references are made:
from the subjects of biographies to the authors;
from the principal anonymous and pseudonymous works to the writer's real names where known;
from works included in, or noticed in the title-pages of other publications, to those publications.

5. To obviate the imperfections necessarily attendant on an alphabetical arrangement, and for the greater facility of reference, short classifications are introduced of the chief subjects on which the books in the library treat, referring to the names of the authors in the same general alphabet; thereby uniting the advantages of the alphabetical and classified systems, and acting in some measure as a key to the prevailing character of the library.

6. All authors' names are followed by full stops: any articles placed under a writer's name, of which he is not the author, but which are anonymous answers to, or criticisms on, his works; anonymous memoirs placed under the subjects; or any entries whatever, in which the heading name prefixed is not that of the author, are distinguished by a line following the name.

7. The headings of the short classifications are distinguished by being doubly underlined with red ink. The name to be referred to is singly underlined, but when the reference is to another heading, and not to an author, it is doubly underlined.

In preparing titles for the catalogue (whether it be intended to transcribe or print them), it should be an imperative instruction that they be written on slips of paper (or on cards) of uniform size. It is also useful to include in them a word or two which may serve to identify the origin of the books—whether by purchase, by copyright, or by gift—and to indicate the date of their respective acquisition.