Home-court advantage is considered as the edge that sports teams seem to gain when they play in their own arenas. Exactly why it happens, though, is a long-enduring mystery. It is a long-enduring puzzle that psychologists and coaches are at a loss to explain. Fans who paint their faces, taunt their opponents, and scream their throats raw may think the answer is simple. More-refined observers--sociologists, psychologists, and statisticians--have proposed all kinds of scientific explanations. Several decades of research suggest that home-court advantage is real, but complex. The author examines the reasons behind the home-court advantage and presents some studies that challenged the conventional wisdom.