The Surangama Sutra is regarded as a very important sutra in the Chan school. It gives both theoretical analysis and practical guidance for practitioners to reach the highest samadhi. By using the three aspects of wondrous samatha, samapatti, and dhyana as a scaffold, it provides instruction on the correct understanding of Buddha nature, the true mind/nirvana, the illusory mind/mundane existences, the ways to reach enlightenment, the Surangama mantra, and the demonic states of mind. This Sutra is a complete and practical manual for meditation practitioners.