This book is designed for researchers and practitioners in the dynamic field of power systems, focusing on optimal reactive power dispatch (ORPD). It provides a comprehensive overview of ORPD, explaining its significance in both transmission and distribution networks. Early chapters introduce ORPD concepts and the importance of optimization in power system analysis, before delving into the complexities of the ORPD problem. The text emphasizes metaheuristic techniques, widely used for their effectiveness in solving complex optimization issues.The book also presents an enhanced nature-inspired algorithm tailored to address ORPD challenges, improving performance and adaptability. Throughout, readers are provided with theoretical frameworks, practical applications, and case studies. In later chapters, the text explores multi-objective optimization, incorporating fuzzy-based methodologies to address conflicting objectives such as cost minimization, loss reduction, and system reliability. The book contributes valuable knowledge on power system sustainability, especially with renewable energy integration.