On the world's fourth largest island, and virtually nowhere else, lives an entire "infraorder" of primates: the three dozen or so lemur species. But Madagascar has radically transformed since another primate—humans—arrived two thousand years ago. Rampant deforestation, habitat fragmentation, and other anthropogenic factors are impacting lemurs much faster than evolution can mitigate the effects. Follow American and Malagasy scientists through the country's remaining forests to learn how these compelling creatures are coping with change.