This book covers three major topics related to prevention of cascading power outages in a power transmission grid: modelling and analysis of cascading failures for reliable and efficient simulation and better understanding of important mechanisms, root causes and propagation patterns of failures and power outages; controlled system separation to mitigate of cascading failures addressing key questions such as where, when, and how to separate; optimal system restoration from cascading power outages and blackouts by well-designed milestones, optimized procedures, and emerging techniques.