This book covers the history of geothermal science, with a special focus on electricity production. The Larderello area, the cradle of the modern geothermal industry, is particularly highlighted. A major portion of the book is devoted to geothermal energy generation in various countries with a specific section on each geothermal field and their major characteristics. The book covers in detail the future development tracks and trends, such as the foreseeable reduction of capacity factor in the forthcoming years, the basic power plant technology (dry steam, single/double flash, ORC/Kalina binary cycle) and the temperature dependence of the conversion efficiency, specially focussed on resource evaluation. Further, the book includes chapters on forecasting of the geothermal potential, both short and long term, and the contribution to CO2 emission reduction. A key aspect of the book is to provide information on critical topics related to geothermal exploitation for electricity and the status of the geothermal industry.