Anthony Aveni's latest book is a clearly written and often fascinating introduction to the archaeoastronomy of Stonehenge in Britain, the Maya of Mesoamerica, and the Inca of Peru. Although the idea that various prehistoric and other structures entailed possible celestial alignments is about 100 years old, it was only during the past three decades or so that systematic studies were carried out. The result has been the new field of archaeoastronomy, now complete with societies, conferences, and journals. Aveni's book is also a brief survey of the history of this discipline, from its early concern mainly with celestial alignments, to its present integration with human cultural history--religion, art, mythology, and astrology. There is something here for both the novice reader and the scholar.

The first chapter introduces the reader to skywatching - namely, naked eye observations of the motions of the sun, moon, planets, and stars. Those knowledgeable about the solstices, lunar standstills, heliacal risings and settings, and such, may skip this chapter. What I like about this chapter, and what makes it one of the best introductions to the subject that I know, is that Aveni presents it totally from a geocentric viewpoint; indeed, the whole book is such, so that Copernicus's name is not mentioned until the last page! This avoids what I see as a pitfall with most discussion of celestial motions; by beginning with the heliocentric solar system, they must resort to showing how the "illusion" of various motions of the sun, moon, and so forth appear along and around the ecliptic. Of course we know the earth revolves around the sun; yet this is entirely irrelevant to skywatching, past or present, which is based on the appearances of things. Every day in the everyday world the sun rises and sets, even though Copernicus was right.

The chapter on Stonehenge is an excellent overview of the archaeology and archaeoastronomy of this prehistoric site, which was built, rebuilt, and modified from about 2900 to 1800 BC. The idea of Stonehenge as an astronomical observatory began with Norman Lockyer in the late 19th century, but went full steam in the 1960s when Gerald Hawkins plugged the alignments into a computer to reveal, supposedly, that the Stonehenge was a computer. Aveni discusses the initial skepticism among some archaeologists, such as Richard Atkinson, as well as his own doubt of Hawkins' claim that Stonehenge can be used to predict eclipses. But Aveni is convinced that it was used as a horizon calendar for correlating the solstices and lunar standstills. Mention is made, but not discussed in any depth, of Alexander Thom's studies of other megalithic sites in the British Isles.

Unfortunately all we can know about Stonehenge astronomy and other megalithic sites is what we infer from the stones. In contrast, Maya civilization, which flourished between about 200 and 900 AD, had a written language and a place value mathematical system with a symbol for zero. But deplorably and tragically the Spanish destroyed virtually all written traces of this "pagan" culture; only four surviving fragments of manuscripts are extant. Although scholars have been studying these manuscripts for most of this century, only in the 1970s was the code finally cracked, so we now may read the Maya language. These writings supplement the records in stone, for the Maya also produced horizon calendars by aligning their buildings to key sightings. In addition to following the motions of the sun and moon, the Maya were obsessed with the planet Venus, measuring its motion to the accuracy of one day in 500 years! (Of course, this is no match for the overzealous guide at Chich? Itza who told me that all the planets, even Pluto, are found in the Maya fragments!) Aveni is convinced that the accuracy of the Maya calendar was such that it (unlike Stonehenge) could be and was used to predict eclipses.

Similarly the Incas in Peru aligned their buildings toward horizon sightings. Here Aveni focuses on the archaeoastronomy of the Temple of the Ancestors (Coricancha) in the valley of Cuzco in the Andes Mountains, where alignments are oriented toward key horizon events of the Sun, Moon, Venus, and the Pleiades. Actually, tracking the heliacal rising of the Pleiades was also common among the Native Americans in North America. They probably used it, along with other celestial events, as an agricultural calendar; Aveni also speculates that the Incas used it as such, telling them when to plow, plant, and harvest.

The last chapter, with the clever title, "The West vs. the Rest," brings the discussion toward the inevitable comparison of these cultures with ours, a product of ancient Greek thought. Specifically, Aveni focuses on a comparison of Greek geometrical and spatial thinking, which gave rise to cosmology, with earlier Babylonian astronomy. As he correctly point out, the Babylonian tradition of detailed trackings of the motions of celestial objects is merely another version of precise naked eye skywatching as found in the Americas. But for some untold reason Aveni finds this "resemblance" to be surprising (p. 182). Furthermore, in his attempt to fit the Greeks into the mythical world of the ancients (pp. 191-2), he overstates his case. True, astrology did not die with the Greeks, yet Aristotle made a valiant effort to categorize it as a superstition. True too, Ptolemy wrote the classic text on astrology (Tetrabiblos), but it was not part of or even mentioned in the Almagest; astronomy entailed accuracy, astrology was hit and miss.

The mention of astrology leads to the important question of the purpose and meaning of skywatching in these "Three Great Ancient Cultures." From the documents, we know that astronomy was, as Aveni states, "inextricably linked to religious pursuits" (p. 145). Following the celestial motions was a way of knowing the gods, a link between the gods and humans in a "reciprocal contract" so that, together, they would "keep the universe in equilibrium" (p.121). The same was probably true for the prehistoric people of Stonehenge. They not only witnessed sunrises and sunsets but also helped to make it happen. As Aveni writes: "I am convinced that if Stonehenge had anything to do with sun and moon astronomy, the association between its architecture and the sky was more closely allied with theater than with exact science" (p. 85). And thus: "If we insist on calling Stonehenge an observatory, then we must label it a sacred observatory" (p. 91). Few scholars, I suspect, would disagree.

Which bring me to a final question that disturbs me but to which I have no answer. The evidence from the writings among the Maya and Inca cultures reveals that despite years of accurate predictions of celestial events they continued the ritual of animal and human sacrifice to appease the gods - or in astronomical terms, to make sure that, say, the sun would return on its northerly journey after reaching the winter solstice. But why not, say among some ancient Mayan "Einstein," was not a hue and cry raised, pointing to the ever faithful heavenly returns and the possibility that such might continue independently of us, so that, in time, sacrificial rituals may be needless. Was it not worth a test, in order to save a child's life? In a sense, is not this world-view one of the treasured gifts from the ancient Greeks? I ask this unanswerable question knowing full well that even asking such questions is not "correct" in this postmodern world.