In recent years there have been rapid strides in our understanding of plate-tectonic processes, many developments in methods of basin analysis, and the accumulation of much new surface and subsurface geological and geophysical data. Projects such as COCORP (in the United States) and Lithoprobe (in Canada) have provided essential insights into the deep crustal structure of the continent. Synthesis of all the available information about North America’s geological regions has not been attempted systematically since the “Decade of North American Geology” project undertaken by the Geological Society of America and the Geological Survey of Canada nearly twenty years ago. The book commences with a summary of the Phanerozoic geological history of the United States and Canada, illustrated with a suite of new paleogeographic maps, and tying in each of the subsequent regional chapters by the inclusion of numerous cross-references. This followed by a set of fifteen regional syntheses of the principal tectonic regions of the United States and Canada, focusing on the stratigraphic and tectonic history of the major sedimentary basins. Most of these chapters have been contributed by specialists, drawing on their own research, and providing interpretive summaries of a type not previously attempted.