Should I create the index for my book myself, or should I hire a professional indexer?
The responsibility for indexing typically falls to authors. Publishers will often provide style and formatting guidelines for authors and indexers. For example, the University of Virginia Press follows the indexing style described in the Chicago Manual of Style, 17th edition, and we also offer press-specific index style and formatting guidance on our website. Ask your publisher for its guidance if not provided to you.
The Chicago Manual of Style’s chapter on indexing covers general principles and offers basic guidelines for preparing and editing an index to a book-length work, and a booklet of the indexing chapter, Indexes, is available from the University of Chicago Press. The American Society for Indexing has also issued a best practices guide, available for free at http://www.asindexing.org/best-indexing-practices.
Most book indexes must be completed between the time page proofs are issued and the time they are returned to the typesetter. An author preparing their own index will have to proofread as well as index the work in that time span—typically about four weeks. Therefore, authors are strongly encouraged to begin work on their index soon after their review of the copyedited manuscript is complete. Although the index cannot be finalized until page proofs are available (because only then are the page numbers final), it is wise to select the terms to be included in the index and set them up in a word-processing file beforehand. Then, once you have the page proofs in hand, you need only add the page numbers.
Another option, of course, would be to hire a professional indexer for this important task. (Your publisher should be able to provide you with contact information for professional indexers with whom they have worked.) Indexers assess their fees based on the total number of indexable pages. If you have access to research or subvention funds, it may be possible to use those to cover indexing costs.
It makes sense to carefully weigh the pros and cons of each approach. The Chicago Manual of Style describes the ideal indexer as one who “sees the work as a whole” and is able to anticipate “what readers of the particular work are likely to look for and what headings they will think of.” As author, you know your subject matter and intended audience best. Some authors enjoy the experience of creating their own index; it can be a new way of interacting with the text. Other authors simply may not have the time (or the inclination) for such painstaking labor or feel uncertain whether they can achieve a sufficiently distant perspective to reflect on their book in this way.