Despite writing almost nothing specifically on health care, clinical psychologist James Reason has influenced modern thinking about medical errors more than any other individual. This book shows why. Although some of the information on error analysis and theory may be too technical for the average reader, Reason’s lucid explanations of complex concepts, his easily accessible examples, and his wry sense of humor make this a must-read for those interested in learning safety theory. His book Managing the Risks of Organizational Accidents is less theoretical and may be more appropriate for the reader interested in an introduction to Reason’s thinking.