Pyramids are now being found almost everywhere: in 1994 in China; then in Caral, in Peru, Southern America; then in Northern Italy and in 2005 in Bosnia. Despite their prevalence, massive pyramids remain as mysterious and controversial as ever. Though Egyptologists continue to argue that the Egyptian pyramids are tombs, no bodies have ever been discovered in them. None of the other pyramids are tombs either. Apart from the Mayan pyramids, which are much more recent, all pyramids are similar in shape, size and age. Does this mean that each culture developed this rather unique shape on its own, or does it mean that there was a truly global movement - somewhere around 3000 BC? This is the first book to explore the new landscape of pyramids found worldwide. It describes the changed nature of the pyramid debate and offers science a challenge, but equally tries to answer some of the key questions raised during the last decade of pyramid discovery. It is a series of discoveries that has changed the archaeological world and extended all our horizons.

This book represents the proceedings of a symposium held at the Spring 1981 ACS meeting in Atlanta. The symposium brought together Theoretical Chemists, Solid State Physicists, Experimen tal Chemists and Crystallographers. One of its major aims was to increase interaction between these diverse groups which often use very different languages to describe similar concepts. The devel opment of a common language, or at least the acquisition of a multilingual capability, is a necessity if the field is to prosper. Much depends in this field on the interplay between theory and experiment. Accordingly this volume begins with two introduc tory chapters, one theoretical and the other experimental, which contain much of the background material needed for a through under standing of the field. The remaining sections describe a wide variety of applications and illustrate, we believe, the central role of charge densities in the understanding of chemical bonding. We are most indebted to the Divisions of Inorganic and Phy sical Chemistry of the American Chemical Society, which provided the stimulus for the symposium and gave generous financial support. We also gratefully acknowledge financial support from the Special Educational Opportunities Program of the Petroleum Research Fund administered by the American Chemical Society, which made exten sive participation by speakers from abroad possible."

This book deals with the electron density distribution in molecules and solids as obtained experimentally by X-ray diffraction. It is a comprehensive treatment of the methods involved, and the interpretation of the experimental results in terms of chemical bonding and intermolecular interactions. Inorganic and organic solids as well as metals are covered in the chapters dealing with specific systems. Encompassing a broad interface with other physical sciences this book will appeal to researchers in crystallography and chemical physics.