This book builds on the cutting edge research presented in the previous edition that was the first of its kind to present the technology behind an emerging power systems management tool still in the early stages of commercial roll-out. In the intervening years, synchrophasors have become a crucial and widely adopted tool in the battle against electricity grid failures around the world.  Still the most accurate wide area measurement (WAMS) technology for power systems, synchronized phasor measurements have become increasingly sophisticated and useful for system monitoring, as the advent of big data storage allows for more nuanced real-time analysis, allowing operators to predict, prevent and mitigate the impacts of blackouts with enhanced accuracy and effectiveness. This new edition continues to provide the most encompassing overview of the technology from its pioneers, and has been expanded and updated to include all the applications and optimizations of the last decade.