Looking for a useful DocBook XML editor, I came across XXE which is not Open Source, but freely available as a “standard edition”. Definitely worth to give it a try.
About Sandro Groganz
Sandro Groganz is an expert in the field of marketing open-source products. He co-founded Age of Peers, a global communications agency for organizations in Open Source. He served as Head of Marketing at Magnolia, creator of the open web content management system Magnolia CMS, Vice President of Marketing at Mindquarry, an open source startup financed by Hasso Plattner Ventures, and Vice President of Communication at eZ Systems, the creator of the open source content management system eZ Publish.