Power quality is an important issue for most of the countries, especially India and other developing countries which suffer from poor quality of electricity supply. Impacts of poor PQ on organization's operational efficiency are significant and disruptive. An overview of different power quality issues, effect of deregulation in electricity supply industries, and impacts of poor PQ in global environments, with a special reference to India are presented in the Book. A review of different methods of power quality monitoring already in use and available in literature has been done. Based on the present complex power system and proliferation of PQ sensitive equipments, it is the need of the hour to have improved and efficient Power quality monitoring and power metering system to allow plants to perform predictive maintenance, energy management, cost management, and quality control. This book will give the readers the concepts of PQ and PQ monitoring. Researchers and readers will get important insights into various PQ phenomena and their monitoring and mitigation techniques.