Archaeoastronomy is a discipline pioneered at Stonehenge and other megalithic sites in Britain and France. Many sites in the southwestern United States have yielded evidence of the prehistoric Anasazi's intense interest in astronomy, similar to that of the megalithic cultures of Europe. Drawing on the archaeological evidence, ethnographical parallels with historic pueblo peoples, and mythology from other cultures around the world, the authors present theories about the meaning and function of the mysterious stone alignments and architectural orientations of the prehistoric Southwest.