Dan Walsh has produced an SELinux colouring book based on one of his articles.
The SELinux primary model or enforcement is called type enforcement. Basically this means we define the label on a process based on its type, and the label on a file system object based on its type. Imagine a system where we define types on objects like cats and dogs. A cat and dog are process types.
It proceeds to describe SELinux clearly and simply. Dan Walsh is the SELinux project lead at Red Hat, and the man who cries every time SELinux is disabled. So you should stop doing that - seriously.