This book presents a systematic human factors-based proactive approach to the improvement of health care work and patient safety. The proposed approach delineates a more direct and powerful alternative to the contemporary dominant focus on error investigation and care providers' accountability. It demonstrates how significant improvements in the quality of care and enhancement of patient safety are contingent on a major shift from efforts and investments driven by a retroactive study of errors, incidents, and adverse events, to an emphasis on proactive human factors-driven intervention and the development of corresponding conceptual approaches and methods for its systematic implementation.