There are two parts of this present book. Part one explains the evolution the concept of the Buddha from Early Buddhism to Mahāyana Buddhism, especially the Lotus Sutra. The concept developed in three steps: 1. an awakened human being, 2. a transcendental being, 3. an embodied dharma. The first step shows us a historical Buddha; the second and third step show us as a philosophical Buddha. The Lotus Sūtra, however, shows us as a religious Buddha who is saving all sentient being. Therefore, the concept of the Buddha had to see the three aspects, which are nirmāṇakāya, saṃboghakāya and dharmakāya. All these aspects, however, are upāya (skillful means) for saving different kinds of sentient beings in the Lotus Sūtra. In summary, the concept of the Buddha developed by necessity of suffering beings. Part two explains the historical background of Korean Buddhism to struggle to adapt in Korean society. There were two periods of Korean Buddhism: the one is the embracive period and the other is the exclusive period. During approximately two millennia of Korean Buddhism, however, the exclusive period is about five hundred years. Even this difficulty period, Korean Buddhism could survive deep inside the mountain. In the period of Japanese colonization (1910-1945), however, Korean Buddhism was challenged to convert to Japanese style of Buddhism. Park Jung-Bin (1891-1943), the founder of Won-Buddhism, tried to reform not Buddhism but Buddha’s dharma for use in the real world since 1916. He enshrined Il-Won-Sang (One circle image, dharmakāya) instead of Buddha image in the main hall. He taught four-fold graces (saṃboghakāya) and three folds studies (nirmāṇakāya) for saving all sentient beings in this scientific civilization. Therefore, Korean Won-Buddhism is succeeding the concept of the Buddha in the Lotus Sutra as soteriological way in this civilization. About the Author Rev. Jeik Hyun has been a Won Buddhist Monk since 2006. He worked as the secretary of the Won-Buddhist Temple of Bangbae, Seoul, South Korea, 2006 2008 and the Won-Buddhist International Training Center of Hawaii, Hawaii, U.S.A., 2009-2012. During that time, he had a followship at East West Center, Asia Pacific Leadership Program, 2011-2012. In 2013,he worked as a manager of the Water Project at Future for the African Children, Eswatini, Africa. He worked at the Won Buddhist Delhi temple in India, teaching meditation to youth from 2014-2017. He finished his M. Phil degree in Buddhist Studies & Civilization at Gautam Buddha University in 2014 and his Ph. D. in2021. He has been working at the Won-Buddhist International Training Center of Hawaii since 2017.