The U.S. Department of Homeland Security, in collaboration with the U.S. Department of State, has prepared this guide to serve as an overview of the approach to critical infrastructure security and resilience adopted in the United States. As attacks on soft targets and crowded places continue across the globe, the need to address current and emerging challenges increases. Therefore, the Department of Homeland Security and Department of State are working together to enhance domestic and global security, with ongoing programs, and recognizing that new approaches may be needed to address these evolving issues.