Zen ? A Cognition to the Mind by Pho Nguyet is a guide to the practice of Sudden Enlightened Zen and the steps that will lead there. This is also recognized as the ?Purification of Mind?. This is explained in the foreword by Bhikku Bodhi: Purification of mind as understood in the Buddha's teaching is the sustained endeavor to cleanse the mind of defilements, those dark unwholesome mental forces which run beneath the surface stream of consciousness vitiating our thinking, values, attitudes, and actions. The chief among the defilements are the three that the Buddha has termed the ?roots of evil? ? greed, hatred, and delusion from which emerge their numerous offshoots and variants: anger and cruelty, avarice and envy, conceit and arrogance, hypocrisy and vanity, the multitude of erroneous views.? Contains deep esoteric spells that give enlightenment that no other books gives.