This book presents Yi Hwang (1501-1570)--better known by his pen name, Toegye--Korea's most eminent Confucian philosopher. It is a pioneering study of Toegye's moral and religious thought that discusses his holistic ideas and experiences as a scholar, thinker, and spiritual practitioner. This study includes Toegye's major texts, essays, letters, and biographies. Edward Chung explains key concepts, original quotations, annotated notes, and thought-provoking comments to bring this monumental thinker and his work to life. Chung also considers comparative and interreligious perspectives and their contemporary relevance. By offering groundbreaking insights into Neo-Confucianism, this book sheds fresh light on the breadth and depth of Toegye's ethics and spirituality, and is an important source for scholars and students in Korean and Confucian studies and comparative philosophy and religion.