EVERY book of a permanent nature, or intended as a work of reference,
requires an index. The length of the Index, or its minuteness, depends
upon the nature of the subject treated, and the importance of making it
easily available to the reader. The Index belongs to the same family
as the Table of Contents, and the Topical Analyses often placed at the
beginning of each chapter: the Contents gives a general idea of the
divisions into which the author has separated his subject; the Topical
Analyses still further divide each chapter; and the Index is ordinarily
still more minute, with the further advantage of having its references
arranged in alphabetical order.
The proper person to make an index is, first of all, the author of the
book, provided that he possesses the natural characteristics. It does
not at all naturally follow, however, that all authors are competent to
do this, for the art of indexing is not as simple as many superficially
suppose. The author should be the one best fitted, because he knows
better than any reader the exact meaning each of his sentences is
intended to convey,--and this meaning should be expressed in the
index. The ideal index is that which gives every topic, thought, or
reference contained in the book itself, without a single superfluous
word, and with no description or comment.
To make an index requires a quick grasp of the idea contained in each
sentence or paragraph, an immediate discernment of the main thought,
an instinctive classification, absolute accuracy in translating this
thought into its briefest expression, ability to condense, and a
sensing of the reader's needs in adequate cross-references. All this
demands a mind more logical and more sensitive to codified detail
than is possessed by many able writers. Under these circumstances,
it is desirable to place the making of the index in the hands of one
possessing these qualifications, either instinctively or as a result of
experience.
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.