Unconventional reservoirs represent a major source of hydrocarbons that can satisfy global energy demand for years to come given the availability of suitable technology for proper hydrocarbon extraction. On average, recovery factors of these reservoirs are typically below 10% compared to 30% for conventional reservoirs around the world. The term unconventional includes shale, coalbed methane as well as tight oil and gas reservoirs. Horizontal drilling and advanced hydraulic fracturing technologies play a significant role in production of these reservoirs. Topics related to unconventional reservoirs including better characterization, geo-mechanical properties, intelligent completions, modeling and analysis, reserves determination, environmental issues for hydraulic fracturing, and production optimization.