One basis of modern medicine is that low doses of many chemicals are beneficial, while higher ones are toxic. And yet a great disparity has evolved with the regulation of many entities — including carcinogens, ionizing radiation, and toxics. Their regulation is based on the notion that that a single molecule or photon is as capable of inducing cancer as the billionth one. How has this disparity happened — with low, beneficial doses being treated and regulated the same way as higher ones? What is correct? One highly compelling look at this subject has emerged from Dr. Edward Calabrese’s painstaking and voluminous research. Using recently declassified Atomic Energy Commission documents, Calabrese details the establishment of the linear no‐threshold model at the height of the Cold War, when thermonuclear bombs were routinely detonated in the atmosphere, resulting in radioactive fallout. His is a spellbinding story of what is often called “noble cause corruption” of science, and of how difficult it is to correct when backed by the might of the federal government.