The work introduces a new approach for shale gas and oil play screening criteria. It combines a mathematically developed approach with geomechanical and geochemical developed indices. An algorithm considers 15 parameters of geomechanical, geochemical and petrophysical properties to assess similarity with the 12 most common shale plays in North America. The approach functions as a metric for quantifying degrees ofsimilarity among the 12 shale plays. It identifies operationally approved methods from analogous reservoir development to increase the potential recovery of shale natural gas and oil accumulations. The book also offers suggestions for future development strategies--Abstract: The work introduces a new approach for shale gas and oil play screening criteria. It combines a mathematically developed approach with geomechanical and geochemical developed indices. An algorithm considers 15 parameters of geomechanical, geochemical and petrophysical properties to assess similarity with the 12 most common shale plays in North America. The approach functions as a metric for quantifying degrees of similarity among the 12 shale plays. It identifies operationally approved methods from analogous reservoir development to increase the potential recovery of shale natural gas and oil accumulations. The book also offers suggestions for future development strategies