Every spring caribou migrate North to the Arctic National Wildlife Refuge in Alaska where tens of thousands of calves are born. The author, who has lived in northern Alaska and has many times observed the migration of caribou, eloquently presents the life cycle of these magnificent animals who travel back and forth through Canada's Yukon Territory and northeast Alaska, almost three thousand miles each year in search of food. The story focuses on a mother caribou and her young, their searches for food through the snows of winter, the mother's protection of the young against wolves and eagles, and the yearly migration patterns of the herd. This engrossing story, resplendent with double-page illustrations, interweaves fascinating information about these mammals, their adaptations for life and travel in the rugged climate of the tundra, the bonding of mothers and their young, the autumnal encounter of males fighting for mates, and the crossing of rivers by the herd along their journey. The "Author's Note" provides information specifically about the Porcupine Herd of caribou, one of the largest migratory herds of North America that is described in this story, as well as mention of the importance of preserving the Arctic National Wildlife Refuge of Alaska.