"The Glowing Foot – The radioactive machine that fit your children's shoes" investigates the "Shoe-fitting Fluoroscope" (or Pedoscope). From the 1920s to the 1970s, these X-ray machines were a centerpiece in shoe stores across America and Europe. Parents and children were delighted to look through a viewfinder and see the bones of their wiggling toes inside new shoes, ostensibly to ensure a "perfect fit." Science writer Sarah Beam exposes the deadly ignorance behind the novelty. The machines were unregulated and often leaked massive amounts of radiation. Sales clerks, who operated them daily, suffered from radiation burns and cancer. The book chronicles the slow realization of the medical community and the quiet disappearance of the machines. "The Glowing Foot" is a cautionary tale about unregulated technology. It shows how the "wow factor" of a new scientific toy blinded a generation of parents to the invisible danger they were exposing their children to, all for the sake of selling leather shoes.