Fair use of a copyrighted work doesn’t infringe. The fair-use doctrine limits all of the exclusive rights in a copyright owner’s bundle. The doctrine’s goal is to provide the breathing room necessary to promote creative expression. Originally developed judicially through common law, fair use was codified in the 1976 Copyright Act (17 U.S.C. §107).

The Copyright Act sets out four factors that must be considered in evaluating whether a use is fair. No one factor is dispositive. Because...