Children are precious in China especially as its population ages rapidly. The unprecedented fast urbanization and massive internal migration have profoundly changed almost every aspect of society. They have impacted the livelihood of children of migrants most. Because of the hukou system and related policies, China's internal migrants face major obstacles to assimilate into cities. But more than that, as this book shows, these policies have also torn families apart on a scale unseen heretofore. More than 100 million children grow up in unstable families and the great majority have suffered from prolonged separation from their parents in the migratory upheaval. This book provides an updated analysis of this mega and painful process unfolding at various geographical scales. The chapters revolve around the central notion of family togetherness, or the lack thereof. The book measures, dissects, and analyses the impacts of migration on children and recommends policies to address major problems from a variety of disciplinary perspectives employing different methodologies. The problems faced by the children of migrants remain enormous, and it is a looming huge crisis in the making. If unaddressed, those problems can damage a whole generation with serious consequences. The chapters in this book were first published in Eurasian Geography and Economics .