Unknown to the general public and ignored by the academic and foreign affairs establishments, Americans once were leaders of religion, education, and intellectual life in Pyongyang, as missionaries who created the foremost Christian community in Northeast Asia. Before the Soviet Union installed an atheist Communist regime in Pyongyang headed by Kim Il Sung, the city was the center of the Presbyterian Church in Asia, and hundreds of thousands of Korean Christians lived there and elsewhere in what is now North Korea. It was a union of Koreans and Americans that set the course that made South Korea the majority Christian...