Abstract: Courts generally insist that two criteria be met before imposing strict liability rather than basing liability on the negligence rule. The first--that the injurer’s activity must be dangerous--is sensible because strict liability possesses general advantages over the negligence rule in controlling risk. But the second--that the activity must be uncommon--is ill-advised because it exempts all common activities from strict liability no matter how dangerous they are. Thus, the harm generated by the large swath of common dangerous activities--from hunting, to construction, to the transmission of natural gas--is inadequately regulated by tort law. After developing this theme and criticizing ostensible justifications for the uncommon activity requirement, the article addresses the question of how it arose. The answer is that its legal pedigree is problematic: it appears to have been invented by the authors of the first Restatement of Torts. The conclusion is that the uncommon activity requirement for the imposition of strict liability should be eliminated.