A complete academic biography and legacy-evaluation of Go-un Choi Chi-won (10th century CE), one of Korea’s most interesting and iconic historical figures. He is considered a hero of traditional Korean Daoist, Buddhist and Confucian culture. Following a remarkably successful career as a brilliant Confucian government official in Tang China and then back in his native Gyeongju, he was one of few Koreans who achieved the highest level of Daoist sage-hood, achieving Shinseon status rather than dying. There are many sites all around South Korea that claim association with him, that he was present there and accomplished some spiritual feat, or presenting veneration of his lofty reputation; some of them sites associated with him are now utilized as cultural tourist sites. It has been difficult for scholars to separate the folklore myths and legends about his life from the solid facts, and make a coherent story out of them -- this does-so in English for the first time. All photos in the E-book are black-and-white.