Who Makes The Book Index
I love a book with a good index--good being the operative word. It's almost always the responsibility of the author contractually to handle the index--at least that's how the first version of your contract will likely read from the publisher. If you can negotiate something different then good. In these days of cost cutting, publishers will look to the author to produce the index or hire someone to create it.
Like most of these specialties, there is an organization for people who index. Their Frequently Asked Question section handles a lot of about this topic and much more. I’m still racing for my deadline but I couldn’t resist adding this information to the Writing Life.