Introduction
PAS is built around the concepts of interfaces and plugins: all possible tasks related to user and group management and authentication are described in separate interfaces. These interfaces are implemented by plugins, which can be selectively enabled per interface.
Plone uses PlonePAS, which extends PAS with a couple of extra plugin types and which adds GRUF compatibility. Since PlonePAS extensions are rarely needed and are subject to change in the next Plone releases this tutorial will only focus on pure PAS features.

