XMLmind XML Editor v7.3 fully supports DocBook 5.1 --now an OASIS standard-- out of the box. More information: http://www.xmlmind.com/xmleditor/changes.html

Curious DITA experts may want to compare DocBook 5.1 assemblies and topics to DITA maps and topics. Tutorial: "DocBook Assemblies and Topics for the Impatient", http://www.xmlmind.com/tutorials/DocBookAssemblies/index.html

Download free Personal Edition from: http://www.xmlmind.com/xmleditor/download.shtml