When the Nuclear Safety Commission in Japan reviewed safety-design guidelines for nuclear plants in 1990, the regulatory agency explicitly ruled out the need to consider prolonged AC power loss. In other words, nothing like the catastrophe at the Fukushima Daiichi Nuclear Power Station was possible—no tsunami of 45 feet could swamp a nuclear power station and knock out its emergency systems. No blackout could last for days. No triple meltdown could occur. Nothing like this could ever happen. Until it did—over the course of a week in March 2011. In this volume and in gripping detail, the Independent Investigation Commission on the Fukushima Nuclear Accident, a civilian-led group, presents a thorough and powerful account of what happened within hours and days after this nuclear disaster, the second worst in history. It documents the findings of a working group of more than thirty people, including natural scientists and engineers, social scientists and researchers, business people, lawyers, and journalists, who researched this crisis involving multiple simultaneous dangers. They conducted over 300 investigative interviews to collect testimony from relevant individuals. The responsibility of this committee was to act as an external ombudsman, summarizing its conclusions in the form of an original report, published in Japanese in February 2012. This has now been substantially rewritten and revised for this English-language edition. The work reveals the truth behind the tragic saga of the multiple catastrophic accidents at the Fukushima Daiichi Nuclear Power Station.It serves as a valuable and essential historical reference, which will help to inform and guide future nuclear safety and policy in both Japan and internationally.