Many years ago, I set out to write a sort of Dear John letter to the drug phenacetin. Phenacetin had been the P in the ACP tablets liberally dished out for whatever ails you by the navy corpsman second class who ran my ammo ship’s sickbay. (The A and C were aspirin and caffeine.) It was part of the formulas for Coricidin, Excedrin, and a prescription drug I took for headaches. Among the analgesics that kept America on the go, it was the sturdy sidekick—the Gehrig to aspirin’s Ruth, the Pippen to its Jordan.