Kenichi Matsumoto wrote the following explanations of Zen, zazen, delusion, and satori. Translated into English by Madoka Chase Onizuka.
The first time through, please read the sections in the order that they appear. This is important to help you avoid misunderstandings that could unintentially turn your zazen practice into something else completely.
1. Introduction--Knowing what Zen actually is will transform your practice
2. Zen 禅
3. Zazen (Sitting Zen) 坐禅
4. Delusion 迷い
5. Satori (Enlightenment) 悟り