Information for Publishers
You probably already know that non-fiction ebooks still deserve indexes and that there's no reason why they shouldn't have them.
Books need indexes because of their subject, their seriousness and their intended readership, not because of the delivery platform.
People who tell you unpaginated texts can't be indexed are talking drivel. Indexes can be anchored to a section of reflowable text (where page size is controlled by the reader) either by sequential code numbers instead of page numbers, by embedding the index term electronically in the text file or by hyperlinking, the same process that allows us to navigate around and between web pages. All are platform-independent.
Some can be prepared without the delays you might be used to. Indexing needn't take weeks. Read about how embedded indexing can deliver a usable index within a few days of finalization of the text.
Embedded indexing has been around of 20 years; XML for 15 so. Indexing has had the tools and was ready and waiting well before ebooks appeared. There are already 21st century indexers skilled in these techniques, as well as in text analysis that matches the way a book is actually read. Some of us might even be working for your competitors... so don't write us off until you have proof that your readers don't care about quality. The experience of reading a non-fiction ebook should improve on the experience of reading the hard-copy version, not fall short as it often does today.
The usual alternative touted for ebooks is keyword search. Sadly, that's based on a paradigm which was discredited decades ago; a crude model still being pushed by IT types who don't seem to read books. Here's an honest assessment of the shortcomings of search vs index. Read that, and you'll never be taken in again.
Two last points are of special interest to publishers. The temptation to add value by merging indexes to your back catalogue is likely to bring problems. Indexes reflect authorial preferences; unless you've already trained your authors to use similar approaches and terminology, there's no reason why the indexers should be compatible either. See our thoughts on selection and amalgamation. Finally, you might look at our advice on not expecting authors to index their own books.