From the author Chris Karakas:
There has always been the necessity to have a definitive guide on PHP-Nuke. This guide describes the installation and structure of PHP-Nuke and the details of customizing the front end to suit the users' needs. The architecture of PHP-Nuke, with its modules, blocks, topics and themes is presented in detail, as well as the interplay of PHP and MySQL for the creation of a mighty content management system (CMS).It also delves into more advanced issues, like the programming of PHP-Nuke blocks and modules, security, acceleration, and optimization. Day-to-day operations and miscellaneous topics are also covered.

Note: Although this is not written specifically for RavenNuke(tm) and it is not current even with php-nuke, there is much to gain from a reference point of view. It is, by far, the most complete/comprehensive reference available on line for php-nuke. The last update to the documentation is August 5, 2005.