In Korea, the only "god" he knew was the country's leader, Kim Il-Sung, and any perceived blasphemy against him could land a person in a prison camp. So when Joseph Kim finally crossed the Tumen river into China, he did what he was told—follow the cross—even though he didn't know what a cross or a Christian was. Kim tells his story in a new book, Under the Same Sky: From Starvation in North Korea to Salvation in America (Houghton Mifflin Harcourt), and at a time when North Korea occasionally surfaces in the headlines for its continuing beligerence towards the...