Every year over 200 million peasants flock to China’s urban centers, providing a profusion of cheap labor that helps fuel the country’s staggering economic growth. Award-winning journalist Michelle Dammon Loyalka follows the trials and triumphs of eight such migrants—including a vegetable vendor, an itinerant knife sharpener, a free-spirited recycler, and a cash-strapped mother—offering an inside look at the pain, self-sacrifice, and uncertainty underlying China’s dramatic national...