In the early 20th century, the average American medicine cabinet was a would-be poisoner's treasure chest. There was 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 the political will) to detect and prevent the crimes lagged behind. All this changed in 1918, when New York City hired its first scientifically- trained medical examiner Charles Norris. Over the course of a decade and a half, Norris and his extraordinarily driven and talented chief toxicologist, Alexander Gettler, would turn forensic chemistry into a formidable science, sending many a murder to the electric chair and setting the standards that the rest of the country would ultimately adopt.