This book speaks to the severe limits of formal design and technology relative to operational skills, experience, and knowledge. The debate over the vulnerability of critical infrastructures has far too often neglected the managerial dimension of public security and business continuity. is the first book about the people who manage for high reliability, namely, those professionals who provide critical services continuously and safely, even during peak demand times or periods of stress. The text draws on one of the most intensive studies of a critical infrastructure within a high reliability framework. This longitudinal analysis examines the California electrical gridone of the largest, most complex, and economically important in the world. From this research comes a new perspective on strategic balances in society, and practical advice to researchers and professionals who confront reliability daily.