How does a believer or community encounter the God of mission, develop mission awareness, and ultimately commit to the mission of God? When the world church planned and organized the Edinburgh Centenary celebration in 2010, "Mission Spirituality and Authentic Discipleship" was the only added new study topic to the 1910's original ones. With the radical shift in global Christianity in recent decades, how then would the "new" churches in the South rise to be the forerunner of Christian mission with more than two-thirds of the world's Christians? As a Pentecostal missionary from Korea, the author reflects on his journey of mission formation within his unique socio-cultural context. The book argues that the process of one's mission formation gives birth to mission theology and the resultant mission practices. Recognizing the pivotal role of the Holy Spirit in the entire process, the book continues Mission in the Spirit, the main title of the earlier book co-authored with his wife, Julie C. Ma.