A product hurt someone, and the first instinct is to throw it away, fix it, or send it back to the manufacturer. Each of those instincts destroys the case. This article explains what a product liability claim actually requires and where these cases are won and lost. It covers the three theories — manufacturing defect, design defect, and failure to warn — and why they demand completely different proof. It explains the two competing design defect tests, why the reasonable alternative design requirement decides most design cases, and why the warning claim so often fails on causation rather than on the adequacy of the warning. It covers the evidence problem that dominates the practice, the chain of distribution and who can be sued, the defenses that actually succeed, federal preemption in the areas where it applies, and the statutes of repose that end claims before anyone knew there was one. It closes with what to do in the first week.