The United States is the global leader in installed geothermal capacity with approximately 3,086 megawatts (MW) of installed capacity, and is expected to continue that leadership in the next decade. Even so, less than 0.5% of the United States' electricity generation currently comes from geothermal resources. Yet, geothermal energy could be an important contributor to a sustainable energy portfolio in the United States. One of the main constraints on geothermal project development is the ability to secure capital. Despite the technology's 50-year history of providing power at the utility scale, challenges remain in raising sufficient capital, especially during the early stages of project development. This book presents a brief primer on geothermal technology and the most relevant policies related to geothermal project development with a focus on geothermal project finance.