A manifesto for the systems-thinking-informed approach to incident and accident investigation, this accessible text is aimed at experts and generalists. A Glossary of Terms explains key concepts. The premise is both unoriginal and original. Unoriginal, because it stands on the shoulders of systems-thinking pioneers - Barry Turner, Bruno Latour, Charles Perrow, Erik Hollnagel, Diane Vaughan and other luminaries. Original, because it is populist: The Systems-thinking for Safety series shows how theoretical insights can help make the world a safer place. Potentially, the series as a whole, and this manifesto text, have agency. True to its mission to affect change, the book uses case studies to demonstrate how systems-thinking can help stakeholders learn from incidents, accidents and near-misses. The case studies of, for example, the Piper Alpha and Deepwater Horizon offshore disasters, the Lac-Megantic rail disaster, the Fukushima Daiichi nuclear disaster, the United States Navy collisions and the Grenfell Tower fire, demonstrate the universal applicability of systems-thinking. The manifesto argues that the systems-thinking informed approach to incident, accident and near-miss investigation, while resource intensive and effortful, produces tangible safety benefits and, by ensuring that "right is done", delivers justice and closure.