This chapter describes the beginning, evolution, and current practices and theology surrounding Mormon missionary work. During the 1830s and 1840s, while the Latter-day Saints gathered and scattered throughout New York, Ohio, Missouri, and Illinois, Joseph Smith encouraged evangelism. New converts, the products of missionary work themselves, embraced their missionary responsibilities and went forth on their own. The chapter focuses on the activities that Mormon elders and sisters employ as they evangelize both non-Mormon Christians and non-Christians alike. Six points that distinguish Mormon missiology from that of traditional Christian groups are explored: evangelistic practices, personal backgrounds, roles of women, missionary training, financial arrangements, and human deployment. Recent developments in the deployment of both men and women and their teaching plans are likewise described, including the modern expansion and growth of missionary training centers.