In the early 20th century, the average American medicine cabinet was a would-be poisoner’s treasure chest: radioactive radium in health tonics, thallium in depilatory creams, morphine in teething medicine and potassium cyanide in cleaning supplies. While the tools of the murderer’s trade multiplied as the pace of industrial innovation increased, the scientific knowledge (and political will) to detect and prevent the crimes lagged. This changed in 1918, when New York City hired its first scientifically trained medical examiner, Charles Norris. Over a decade and a half, Norris and his chief toxicologist, Alexander Gettler, turned forensic chemistry into a formidable science, sending many a murderer to the electric chair and setting the standards that the rest of the country would ultimately adopt. Based on the best-selling book by Deborah Blum.