This book provides comprehensive information about the key exploration, development and optimization concepts required for gas shale reservoirs. It includes statistics about gas shale resources and countries that have shale gas potential. It addresses the challenges that oil and gas industries may confront for gas shale reservoir exploration and development. It introduces petrophysical analysis, rock physics, geomechanics and passive seismic methods for gas shale plays. It details shale gas environmental issues and challenges, economic consideration for gas shale reservoirs. It includes case studies of major producing gas shale formations.