QUESTION. QUESTION AUTHORITY. QUESTION SOCIETY. QUESTION REALITY. QUESTION YOURSELF.
Question your conclusions, your judgements, your answers. Question this. If you question everything thoroughly enough, the truth will eventually hit you upside the head and you will KNOW. But here's a warning: It won't be what you imagined. It won't be even close.
This is not the same old crap you've seen in a thousand books you don't want to read. This is Zen for people who don't give a rat's ass about Zen. This is the real deal.