Hwadam Seo Gyeong-deok (1489-1546) was one of the most original figures in the early development of Korean Neo-Confucianism. Despite his intellectual significance, his philosophy has remained largely unknown outside Korea and is frequently overlooked in broader accounts of Confucian thought.This volume examines the life, writings, and philosophical orientation of Hwadam Seo Gyeong-deok within the intellectual context of early Joseon Korea. The study focuses on his distinctive understanding of qi and his rejection of dualistic interpretations that subordinate qi to li. Particular attention is given to his articulation of the Great Void as qi, through which he developed a coherent and internally consistent philosophical position that set him apart from many of his contemporaries.Grounded in close readings of primary classical sources, the book reconstructs Hwadam Seo Gyeong-deok's conceptual framework with careful attention to historical context and textual precision. Rather than offering a general survey, it presents a sustained interpretation of his thought and clarifies its place within the broader discourse of Neo-Confucian philosophy.Written for scholars, graduate students, and serious readers of East Asian philosophy, this volume contributes to a deeper understanding of Korean Neo-Confucianism and its significance within global intellectual history.