This book provides a comprehensive yet accessible overview of all relevant topics in the field of radiation protection (health physics). It serves as an essential handbook for practicing health physics professionals, and is also ideal as a teaching text for courses at the university level. The author's website contains materials for instructors including PowerPoint slides for lectures and worked-out solutions to end-of-chapter exercises. The text is organized into clear sections and subsections which can be easily followed and selected for individual study. The book presents the most up-to-date treatment of the topics and references to the literature. One chapter is devoted to Environmental Health Physics, which was written in collaboration with leading professionals in this area.