The False Claims Act was passed in 1863 to stop contractors from selling the Union Army sawdust-filled gunpowder, and it now recovers billions a year, most of it in health care. This article explains why: the statute pairs treble damages and per-claim penalties with a bounty that lets private citizens sue in the government's name and keep a share. It works through the liability provisions and the definition of knowledge that reaches deliberate ignorance and reckless disregard, then takes up the two doctrines that decide modern cases — implied false certification and the rigorous materiality standard of Universal Health Services v. Escobar, and the subjective scienter holding of United States ex rel. Schutte v. SuperValu that closed the good-faith-lawyer defense. It walks the qui tam procedure from the sealed complaint and the written disclosure statement through the government's intervention decision and its newly confirmed power to dismiss over a relator's objection after Polansky, and explains the first-to-file and public disclosure bars that eliminate more cases than the merits. It closes with damages arithmetic, the Anti-Kickback Statute overlay that makes health care the center of the practice, the retaliation claim under Section 3730(h), and the parallel whistleblower programs at the SEC, CFTC, and IRS.