As the younger son of his father’s third wife, Kim Jong Un was an unlikely heir to the North Korean throne, but from the regime’s perspective, he turned out to be a brilliant choice. He has taken over his grandfather and father’s dynastic cult of personality; reportedly killed, imprisoned, or brought to heel the senior advisers he inherited; maintained the system of hereditary political castes and the gulag; tightened the country’s borders; heightened surveillance of ordinary citizens; restored some economic dynamism; fostered a small moneyed class of supporters; pushed forward missile and nuclear weapons testing; evaded global sanctions; resisted Chinese pressure; and run rings around two U.S. presidents. To figure out how Kim has done it all, Fifield tracked down his aunt and uncle, who run a dry cleaning shop in the United States; interviewed his schoolmates from Switzerland; spoke with the business partner of Kim’s assassinated half brother, Kim Jong Nam; and visited North Korea 11 times. The North Korean system, Fifield concludes, is strong enough to last for a long time. The biggest questions concern the state of the economy and Kim’s health. If he survives to hand power to a fourth generation, the man Fifield labels “the most Machiavellian figure of our time” will have achieved a remarkable feat.