Every publishing-house and most printing establishments of any consequence are in a position to have indexes prepared when required, but the danger is always present that the indexer, approaching his subject from the outside, will fail to place himself sufficiently in the author's attitude, and thus lessen the value of his work. It is most desirable, in order to prevent this, that the author carefully inspect the index while in manuscript. He can thus detect possible departures in the indexer's condensed expression of his own thought.
The following rules and suggestions are given with a twofold object in mind: _first_, to prevent those authors who possess the necessary qualifications from avoiding the preparation of their own indexes because of unfamiliarity with the technical details; _second_, to enable authors intelligently to criticize the form as well as the matter of those indexes which are prepared for their volumes by other hands.
The closeness with which a book is to be indexed depends partly upon the nature of its contents and partly upon the ideas of the author or publisher. Some indexes contain only the page references; some are so analytical that a reader can gain an excellent idea of the subject-matter itself. These, however, represent the two extremes. The ordinary index aims to give every reference necessary to enable the reader to locate easily the subject-matter for which he searches, but not a synopsis of that subject-matter. The entries should cover, then, with more or less minuteness, as desired, the following:
(_a_) Proper names, whether of persons, places, religious or political bodies, etc. (_b_) Events and periods. (_c_) Titles of books to which reference is made. (_d_) Specific topics or subjects. (_e_) Definitions. (_f_) Vital statements.
The indexer should decide definitely in his mind just what his procedure is to be before actually beginning work. At first, it is well to make the index too full rather than the reverse, as it is easier to cut out than to fill in. Most important of all, he must be sure that the matter to be indexed is clearly understood before he attempts to transcribe the idea. The character of the book to be indexed must be carefully considered, taking into account the class of people who will probably consult it, and the lines on which they will probably seek information.
