Fred Brown
I write indexes for books and technical documentation created in DocBook.
Several years ago, I started experimenting with DocBook indexes on a SuSE linux system. It took me a week to setup DocBook SGML — actually 39 hours and 55 minutes trying to figure things out and then just 5 minutes getting it installed and working.
I ran some tests on how well the DocBook SGML system handled various aspects of indexing and then published the results in an article on my web site. While DocBook SGML looked promising, some significant issues remained to be addressed in how it handled indexes. Some years later, SitePoint found my article and enquired if I'd do indexing in DocBook XML for them. Notably, significant improvements had been made in how DocBook XML and related software handle indexes. For example, you can now specify the sort order of specific index headings.
My DocBook clients include O'Reilly Media and SitePoint.