Volume 60 of Reviews in Mineralogy and Geochemistry assesses the current state of knowledge of lunar geoscience, given the data sets provided by missions of the 1990's, and lists remaining key questions as well as new ones for future exploration to address. It documents how a planet or moon other than the world on which we live can be studied and understood in light of integrated suites of specific kinds of information. The Moon is the only body other than Earth for which we have material samples of known geologic context for study. This volume seeks to show how the different kinds of information gained about the Moon relate to each other and also to learn from this experience, thus allowing more efficient planning for the exploration of other worlds.

The only work to date to collect data gathered during the American and Soviet missions in an accessible and complete reference of current scientific and technical information about the Moon.

The simple question "How did the Maya come up with a calendar that had only 260 days?" led Vincent Malmström to discover an unexpected "hearth" of Mesoamerican culture. In this boldly revisionist book, he sets forth his challenging, new view of the origin and diffusion of Mesoamerican calendrical systems—the intellectual achievement that gave rise to Mesoamerican civilization and culture. Malmström posits that the 260-day calendar marked the interval between passages of the sun at its zenith over Izapa, an ancient ceremonial center in the Soconusco region of Mexico's Pacific coastal plain. He goes on to show how the calendar developed by the Zoque people of the region in the fourteenth century B.C. gradually diffused through Mesoamerica into the so-called "Olmec metropolitan area" of the Gulf coast and beyond to the Maya in the east and to the plateau of Mexico in the west. These findings challenge our previous understanding of the origin and diffusion of Mesoamerican civilization. Sure to provoke lively debate in many quarters, this book will be important reading for all students of ancient Mesoamerica—anthropologists, archaeologists, archaeoastronomers, geographers, and the growing public fascinated by all things Maya.