Stonehenge is surely the most obvious and best known, but there are many other monumental structures and megaliths that played integral roles in the astronomical rhythms of ancient cultures. Archaeoastronomy is the new academic discipline intended to examine prehistoric cultures that reached for the heavens, and this describes the scientific findings thus far. In a series of chapters that read like graduate lectures, we learn that: the Egyptian pyramids may have been as much astronomical edifices as funeral structures; the aesthetically ""hideous"" Carocol Tower of Chichen Itza in Yucatan is the most beguiling of Mayan astronomical structures; and the massive medicine wheels of Rocky Mountain Indians and the humped mounds of the Mississippi Valley were astronomically related. Krupp details the early research methods and scientific speculations and outlines how the science of each, including carbon dating, has come of age. And because of its mystery and the long scientific interest in Stonehenge, the book's main emphasis is on that structure. Beginning with its prehistory with the Windmill Hill people and the Beaker People, its ""decoding"" by Hawkins, and the revelations of a painstaking amateur who was retired and ""looking about for something to do,"" the book offers a portrait of Stonehenge as a remarkable computer, able to predict eclipses as well as lunisolar alignments. Along the way, Krupp takes on various fanciful, unverifiable claims, such as Velikovsky's unworldly collision scenario. For the non-cognoscenti, it is occasionally tough going but nonetheless worth the effort.