RE: DOCBOOK-APPS: content creation

> > Anyone know of any good gui tools where I can just 
> concentrate on the
> > content (and maybe some that run on OSX, and don't cost too much)?
> 

https://sourceforge.net/projects/swiesnerxmlgui/

It is free and written in Java (though optimized for Windows), so it
should fit your needs.
You can just add your XSLT style and transform using the style of your
choice with a mouse click.

Stephan