Ive tried my hand at a number of open-source content management systems, and I can report without hesitation that Plone is my favorite.
This Zope-based CMS is simple to install and ready to be useful right out of the box, but just as compelling is Plones potential for extension and customization.
Ive recently been reading Andy McKays "The Definitive Guide to Plone," a solid resource for tapping Plones potential.
This 568-page volume, priced at $45, deals with all the Plone installation and configuration fundamentals and covers important topics such as template customization, basic scripting and authenticating users against current user stores and directories.
In addition, "The Definitive Guide to Plone" has good chapters on how to manage workflow, which is one of Plones significant strengths as a content management system.
Whats more, McKay provides a thorough treatment for managing security for a Plone site.
I would like to see additional coverage of the add-on products that are available for use with Plone, such as those for setting up Wikis or running an iCal calendar server, but I can recommend "The Definitive Guide to Plone" as a good beginning point for developing dynamic sites that are based on Plone.
For further information about McKays "The Definitive Guide to Plone," browse to www.apress.com.