This textbook is a comprehensive resource designed for university master's students on power systems, with a focus on engineering-related aspects. It covers all the fundamental principles of power systems economics. PhD students seeking to enhance their understanding of power systems economics from an engineering standpoint will also benefit from this book. It offers in-depth analysis and detailed insights into economic engineering aspects, presenting various models that are meticulously explained. Furthermore, practising engineers from all disciplines will find this book useful as it provides practical solutions to real-world engineering issues. Through worked examples and solved problems derived from existing installations, professionals can apply the knowledge gained in their everyday work. From a broader perspective, the book caters to the growing number of individuals interested in the economics of power systems, whether driven by professional obligations or self-education. What sets this book apart from existing literature is its unique approach, establishing a strong connection between economics and engineering. Unlike traditional texts that predominantly focus on economic theory, this book bridges the gap by offering practical applications within the power system context. The first part looks into classic economic theory, exploring subjects such as producers and consumers, market behavior, and general market structures, always with a clear connection to power systems. Numerous examples from the power system industry enrich the learning experience. In the second part, the theory presented in the first section is applied to power system-specific problems. These include an in-depth examination of different costs in power systems, regulation strategies, and the intricacies of electricity markets. Overall, this book provides a valuable resource for universitystudents, PhD candidates, and engineers alike, offering a unique blend of economic theory and engineering applications.