The XML Trenches posts are case studies of real-world publisher XML events. The idea is to illustrate the fact that digital content strategies need the right tools and approach, and are a guide to help publishers make the right decisions.
We just received a DocBook XML file from a publisher who asked, "Can this be used to make a Mobipocket for Amazon?". The DocBook XML had already been used by the producer to make an ePub. We cracked it open to have a look.
It was a valid and well-formed DocBook file with a custom namespace, but there were significant tagging and structural errors which stop it being usable except by spending time = money. I have posted on this before in Sustainable XML Strategies.
This is the issue with every DocBook produced book XML I have ever seen. They cannot be used to produce more outputs without significant analysis, time and more work.