Librarians and other large buyers judge the quality of a book based on its index. And they know a bad one from a good one.

Also, because the index is free to view on Amazon, readers use it to see if your book has what they want.

Both of these mean one thing — good indexes sell books.

A book index can add or take away from your book. It can also do the same to your reputation.

Just like every other part of the book, the index speaks to you as an author. A good one will enhance the quality and professionalism of your book, while a bad one can hurt it.

Think of an index like a living appendage to your book. It’s an integral part of the whole, so you should treat it with the same care you treat the rest of the book.

Don’t let a deadline or other pressures put a blemish on your work.

Your reader expects an book index.

Not only that — they also use it. Indexes make referencing (and citing) information a lot easier.

A good index that considers all possible readers, what they’re going to look up, and how they’re going to do it is invaluable to readers. And it makes your book that much more complete.