The bromide "nothing is constant but change" could have been coined to describe the geological history of the Permo-Carboniferous - the Mississippian, Pennsylvanian, and Permian Periods. Global tectonics, fluctuations in atmospheric and oceanic chemistry, changes in global climate, and evolutionary changes in survivors of mass extinctions created the backdrop for the shifting panorama of the remarkable time in earth history. Catastrophic extinctions during the Frasnian-Famennian crisis decimated the global plant and animal populations, leaving survivors to initally struggle through the Devonian-Carboniferous transition. The ensuing evolutionary diversification into less-populated niches was brought to an abrupt end at the close of the Permian Period by the largest of all mass extinctions. Upheavals in plate motion change the configuration of continents and oceans during this time. Within the evolving Permo-Carboniferous "landscape," a wide diversity of carbonate platforms and reefs flourished. They ranged in size from small mounds to mega-platforms, some of which are important mineral and petroleum reservoirs. It is the diversity which Permo-Carboniferous rocks offer that has led to their intensive study by researchers from industry and academia around the globe. This book stems mostly from presentations given at the SEPM- and IAS-sponsored research conference Permo-Carboniferous Carbonate Platforms and Reefs, held May 12-19, 2000 in El Paso, Texas.