Here's a tip: start the index when you start writing the book. All you need is an alphabetical list. Then you can do the index very quickly when it is time, simply by filling in the page numbers for each entry.
You can take your bibliography, copy and paste to another document, and then leave only the names and some titles of works. Then you have an outline of the index in alphabetical order. You can add to the index at the same time as you compile the bibliography.