This book is a comparative, historical, and theological evaluation of the nature of the church and ministry in the theology of John Calvin and John Wesley, and its implications for the Seventh-day Adventist Church. The study is significant in the sense that the impact of Calvin and Wesley concept of the church and ministry on the Adventist Church has not been explored. The introductory chapter examines the lack of consensus among Christians as to what ministry means and who the ministers are. The other chapters(chapter 2) espouses the nature of the church and ministry in the Bible and the history of the church to help ascertain why there was a need for a clearer ecclesiology and ministry from Calvin and Wesley. Chapters 3 and 4 expound the church and ministry in the theology of Calvin and Wesley. Chapter 5 compares Calvin and Wesley's views on the church and ministry to help identify views in their thoughts that can or have impacted the Adventist Church. Chapter 6 synthesizes the ecclesiological views of Calvin and Wesley and their implications for the SDA Church. Chapter 7 is a summation and conclusion of the study.