North Korean sailors help local farmers in preparing corn seedlings for planting at a cooperative farm in Kangwon Do, east of the North Korean capital of Pyongyang.

As North Korea's isolation increased, so did the government's obsession with exercising absolute control over its citizens. The housing, job and medical care a citizen received was contingent upon whether the person had been classified as "core," "wavering" and "hostile" to the regime — with half the population in the two suspect categories.

The government ostensibly encouraged citizens to write to it about grievances — and then secretly assigned handwriting experts to pinpoint the identities of anonymous malcontents. A person and his or her entire family could be denounced as traitors for the slightest of transgressions. The regime's "Ten Great Principles of Unique Ideology," for example, dictated that anyone, even a child, who tore or otherwise defaced a newspaper photo of Kim Il Sung or his son, Kim Jong Il, was a political criminal. Families were required to display pictures of the two Kims in their homes, under penalty of having to write a year's worth of self-criticisms.

And the regime's network of labor camps, started in the 1950s, continued to swallow up hundreds of thousands of North Koreans, who were forced to work 16 hours a day and endure grisly tortures, such as having their stomachs filled to bursting with water. In addition to instilling fear and submissiveness in the North's population, the camps also were an industry unto themselves; prison laborers worked in mines and gathered medicinal herbs for trade to China, and were also rented out to Soviet logging camps in Siberia.

To prevent any ideas that might challenge Kim Il-Sung-chui, the North Korean regime tightly restricted contact with the outside world — reportedly, to the extent of producing radios that were preset to tune in only to North Korean stations.