For meditators who have gained experience and some progress in vipassana meditation, this brief and clear exposition of the stages of Vipassana insight will be an invaluable guide.
Many vipasanna meditators do not know, and teachers also do not inform them, that there are actually 16 stages of vipassana insight-knowledges leading to Nibbhana, which corresponding to 7 stages of purification. These 7 stages of purification were first delineated as a sequence by the Elder Punna Mantaaniputta, who likened them to relay chariots in a conversation with Sariputta, as recorded in the Rathavinita Sutta, the 24th discourse of the Majjhima Nikaya. In his encyclopedic treatise on Buddhist meditation the "Vissuddhi-Magga", the great commentator Buddhaghosa expands upon these 7 stages, interlacing them with 16 insight-knowledges. Together they serve as an outline of the entire path a meditator goes through on his inner journey to liberation. If one's practice is correct, one will progress according to these stages of insight and purification. These are stages with clear signs that can be experienced in one's own body and mind, and therefore verified for oneself.
This treatise, which began as a brief list that was only given out to more advanced meditators at Mahasi Sayadaw's meditation center, is a succinct summary of these 7 stages of purification and 16 insight-knowledges. It's purpose is to allow meditators to accurately gauge their progress, and thereby understand clearly where they are on the path to Nibbhana. By expanding upon the list and then allowing its publication, the Sayadaw has, once again, done all vipassana meditators a huge service. This treatise functions like a beacon on the path, showing where you have traveled, and where you have yet to go.
The book is available for download on the Internet. Refer to it only after gaining some definite insights and progress on the path. Otherwise, it will be like reading a menu of foods that you have never seen nor tasted before. It will not help one's practice if read prematurely, as it might introduce thought and expectations about the path that will hinder progress. If you have not yet achieved definite progress in insight, store this away for future reference and just practice. One day, this will become very useful, and when it does, you will know when to refer to it. How do you know you have achieved definite progress in insight?, you might well ask. Well, when you have experienced certain, very definite things in meditation that are not a result of your imagination and are quite outside your normal range of experience and understanding, and you find yourself wondering or somewhat confused about whether you have reached Nibbaana or somewhere closer to it, at that time, this book might come in handy.