As Holly Tucker tells it in City of Light, City of Poison: Murder, Magic and the First Police Chief of Paris, the state of the capital made the would-be glorious Sun King of France, Louis XIV, look bad, and he wanted it fixed. And so La Reynie was installed as lieutenant general of police and assigned to get the crime under control. The book tracks his efforts, beginning with fairly straightforward measures like lighting the streets. But gradually he realized he faced a bigger case. Imagine one of those complex modern multi-agency investigations involving violent motorcycle gangs with their fingers in narcotics and illegal weapons and God knows what else, but swap in rogue midwives, fortune-tellers, dodgy priests—and poisoners. The book reads like Law and Order: 17th Century Parisian Poisoners Unit.

La Reynie discovered that there was a neighborhood where you could go if you wanted face-whitening creams, love potions, abortions, or even a little something to make your husband drop dead. And it wasn’t just local women shopping for these services, either—sometimes it was women of the court and perhaps even mistresses of Louis XIV himself. The further La Reynie dug, the more gruesome the allegations became. How high did the Affair of the Poisons go? Was the King himself in danger?