A Korean-American Protestant minister named John Yoon was banned from entering China after police broke into an apartment he rented close to the Korean border and found 19 North Korean refugees hiding there.

Back in Seattle, he wondered how to resume his work of helping the refugees escape. He came up with the idea of changing his name to Phillip Buck, obtained a new U.S. passport and returned to the city of Yanji, Jilin province, to resume his labors.

Yoon – or Buck – continued until May 9, 2005, when he was arrested for helping illegal immigrants. After 15 months in jail, he was found guilty and deported. “You should not try me,” he told the judge. “The one who should be tried is Kim Jong Il for the murders he committed against his own people. I have only rescued them from drowning.”

That is one of the many extraordinary personal stories told in “Escape from North Korea; the Untold Story of Asia’s Underground Railroad,” by Melanie Kirkpatrick, former deputy editor of the editorial page at the Wall Street Journal.

The book describes how 24,000 North Koreans have escaped from their country since 1953, a small number going to the U.S. and Europe and the vast majority going to South Korea. Kirkpatrick compares their perilous passage to the secret escape route of slaves from the American South before President Abraham Lincoln abolished the practice in 1862.

The book makes remarkable reading in 2012, 20 years after the fall of the Iron Curtain in Europe and the breakup of the Soviet Union. It reads like an account of life in Nazi-occupied Europe, when Jews and other opponents of Hitler’s regime attempted to escape. One word out of place, a friend who turns informer or a bribe that is insufficient – and the person is arrested and sent to a camp and probable death.

Since North Koreans cannot cross the DMZ into South Korea, they have to escape through China, a country that is Pyongyang’s only ally and one that returns them if they are captured. So it is the story not only of the escape from North Korea but through China to a third country – mainly Mongolia, Vietnam, Thailand, Laos or Cambodia – or an embassy or UN office in China.

The refugees arrive in China with little or no money, speaking no Chinese, wearing clothes, their stunted stature betraying their origin, knowing nothing of the country.

So they can only escape with the help of an enormous network of helpers, guides, safe houses and money donated by supporters, mostly in South Korea and the United States. The network takes in the refugee on his arrival and finds a way to move him across China to a third country.

It cost Pastor Yoon US$20,000 to smuggle out 32 North Koreans from Yanji to Thailand. That is US$625 a person.

The journey is dangerous, especially if the refugee is on his own and does not have papers that allow him to be in China. Yoon gave each of the 32 US$150 in 10-dollar bills to pay as bribes to security officials of Laos if they were arrested. Such payments may be needed often.

Christians – from South Korea and the United States -- run almost all of the aid organizations. Much of the informal assistance the refugees receive comes from local Chinese Christians. Since it is against the law to help them, there are few others to whom they can turn for help.

Pastor Yoon is a typical member of the network – Christian, from South Korea or a Korean-American, many of them ministers who believe it is their duty to help the refugees. To operate in China, they need another identity, usually a businessman or teacher.

The wealth of this book is in the details – the personal stories which Kirkpatrick has gathered in dozens of interviews in the United States, South Korea and China. It is the personal stories of the refugees and those who help them that are the most moving and extraordinary.

The subject is never covered in such detail in the mainstream media.

The author also deals with other groups of North Koreans who want to escape. Since the late 1960s, 250,000 have gone to work in the Russian timber industry, with the profits shared between Pyongyang and Moscow and the workers themselves earning a pittance.

They work in camps that are an extension of North Korea, watched by their own security agents and obliged to attend political classes as at home. Kirkpatrick discusses the fate of the 82,000 South Korean soldiers captured in the North during the Korean War. A small number have succeeded in escaping to the south; one had spent 45 years in captivity.

She also describes the trade in North Korean wives sold to Chinese men who cannot find them at home, for about 20,000 yuan. Such a marriage may be better than being back.

The story is about the heroism of individuals and not governments. While the constitution of the Republic of Korea obliges it to accept refugees from the North, its consulates in China turned some away between 1998 and 2008; its government was pursuing a ‘sunshine policy’ to the North and did not wish to offend Pyongyang.

The Chinese government too is ambiguous. While its stated policy is to repatriate illegal immigrants, it has allowed tens of thousands to remain. A document of its border police of January 2005 that was leaked put the figure at 400,000. Implementation of policy is inconsistent, depending on individual officials and political imperatives.

We should congratulate Kirkpatrick on an excellent piece of research and reporting, throwing light on an extraordinary world that is hidden from sight.