The strength of this evidence is that it covers a wide period, beginning in the separation of North and South Korea until the time of Kim Jong-Il. So we exceed the vision only in the recent period but also looking into its origins.
These people who fled North Korea were not necessarily against the regime, sometimes fervants supporters of it. We follow their (over) life in this country that is sinking into poverty and starvation for many years. Because one of the lessons about North Korea is that the country has not been as poor Always On. Kim-Il-Sung to his early managed to feed its population, provide their heating and electricity, hospitals, educational system, etc ... all of course with the famous and ultra-repressive authoritarian regime. The North Koreans had to obey without thinking but at least had the minimum.
Then allied regimes (USSR, China) moved away or gradually cutting disparaissèrent food this Korea. So the dictatorship remained without food ... Poverty, famine, disease, corruption, despair. If hell is not on earth, North Korea has become in an overview.
Note that the book ceases before the death of Kim Jong-Il and thus there is some years now. To see how the situation has evolved in recent years ... Anyway an excellent book.