This book explores the human contribution to the reliability and resilience of complex, well-defended systems. Usually the human is considered a hazard - a system component whose unsafe acts are implicated in the majority of catastrophic breakdowns. However there is another perspective that has been relatively little studied in its own right - the human as hero, whose adaptations and compensations bring troubled systems back from the brink of disaster time and again. What, if anything, did these situations have in common? Can these human abilities be 'bottled' and passed on to others? The Human Contribution is vital reading for all professionals in high-consequence environments and for managers of any complex system. The book draws its illustrative material from a wide variety of hazardous domains, with the emphasis on healthcare reflecting the author's focus on patient safety over the last decade. All students of human factors - however seasoned - will also find it an invaluable and thought-provoking read.