This book explores the cyber security needed for cyber-physical systems (CPSs), with a focus on results of research and real-world deployment experiences. It addresses CPS across multiple sectors of industry. Cyber-physical systems have emerged from traditional engineered systems in power and energy sectors, automotive, healthcare, and aerospace. In general, these CPS are mission-critical: their availability and correct operation is essential. This book focuses on the security of such mission-critical CPS. The book will bring engineering and IT experts together that have been dealing separately with these issues.