The Buddhist master Chinul (1158-1210) is regarded as one of the greatest Son (Zen) monks in Korea. Included in the study is a thorough study of the life of Chinul, focusing on the reform movement which he launched in the latter half of the 12th century. This history of Chinul is followed by an exposition of his philosophy and approach to Son. Finally, the volume deals with the fascinating story of the legacy which Chinul has left for the Buddhist tradition, a legacy that still continues among the large and active group of monastic institutions in Korea.