The concept of seeing the world as peo­ple groups is arguably the most significant thought innovation in twentieth century missiology. Yet almost 50 years after the launch of the frontier mission movement, fewer than 4% of global missionaries work among “unreached people groups” (UPGs). In view of multiple and contested mission priorities, why prioritize cross-cultural disciple making among least reached peoples? How can healthcare workers make a difference on the edges of the Kingdom?