Book excerpt: ​This book provides the first comprehensive view of safe and secure CPS and IoT systems. The authors address in a unified manner both safety (physical safety of operating equipment and devices) and computer security (correct and sound information), which are traditionally separate topics, practiced by very different people. Offers readers a unified view of safety and security, from basic concepts through research challenges; Provides a detailed comparison of safety and security methodologies; Describes a comprehensive threat model including attacks, design errors, and faults; Identifies important commonalities and differences in safety and security engineering.