Available at any corner shop for little money and, because tasteless, difficult to detect in food or drink, arsenic was so frequently used by potential beneficiaries of wills in the first half of the nineteenth century that it was nicknamed "the inheritor's powder." But after wealthy George Bodle died under suspicious circumstances, leaving behind several heirs, the chemist James Marsh was brought in to see if he could create an accurate test pinpointing the presence of arsenic and put this Victorian scourge to rest.

Incisive and wryly entertaining, science writer Sandra Hempel brings to life a gripping story of domestic infighting, wayward police behavior, other true-crime poisonings, and an unforgettable foray into the origins of forensic science. She also solves this almost two-hundred year-old crime.