Sometimes, reading the news, it seems we are drowning in a sea of risks. Every day, dozens of news articles proclaim some activity, some exposure, some change in the environment exposes us to new and terrifying risks. And every day, governments in developed countries pop out regulations to ensure that we make those changes in behavior to address those supposed risks, whether we want to or not. You probably think such claims, and regulation of risk are backed up by something resembling actual real-world evidence of harm. You probably assume that governments, when regulating, are relying on hard data: physical observations of exposures to a potential harm, physical measurements of harms that result from exposure, and that sort of thing. But if you assume that, you are probably wrong. Since the computer revolution of the 1970s, actual hard evidence of risk have been replaced, both in the estimation of risks, and in the regulation of risks, with computer models simulations of reality - that may have little or no relation to the actual reality in which actual people live. The book is about the influence of computer risk-modeling on public policy, specifically, the giant gushing fountain of EHS regulations that have poured forth since the 1970s. That shift to simulation of risk has led to a massive increase in regulation: a Plague of Regulation that rests on the Plague of Models.