The author, a New York Times reporter, traces the invention and mass distribution of the AK-47 assault rifle, and its effects on war. He traces the invention of the assault rifle, following the miniaturization of rapid-fire arms from the American Civil War, through World War I and Vietnam, to present-day Afghanistan, where Kalashnikovs and their knockoffs number as many as 100 million, one for every seventy persons on earth. It is the weapon of state repression, as well as revolution, civil war, genocide, drug wars, and religious wars; and it is the arms of terrorists, guerrillas, boy soldiers, and thugs. From its inception to its use by more than fifty national armies around the world, to its role in modern-day Afghanistan, he discusses how the deadly weapon has helped alter world history.