Sheets v. Selden was a United States Supreme Court case that dealt with copyright infringement. The plaintiff, Selden, had written a book that contained a system of bookkeeping. The defendant, Sheets, had created a similar system and published it without Selden's permission. Selden sued Sheets for copyright infringement. The Supreme Court ruled in favor of Sheets, finding that the system of bookkeeping was not copyrightable. The Court reasoned that the system was a method of operation, and not an expression of an idea. Therefore, it was not protected by copyright law. The Court also noted that the system was not novel, and that it had been used by others before Selden. The ruling in Sheets v. Selden established an important precedent in copyright law. It established that ideas, processes, and methods of operation are not protected by copyright law. This ruling has been cited in numerous subsequent cases, and it remains an important part of copyright law today.

In Sheets v. Selden, the Supreme Court was asked to decide whether a bookkeeping system created by Charles Selden constituted copyright infringement of an earlier work authored by George Sheets. The majority opinion held that while the two works were similar in purpose and content, they differed enough for Selden's work not to be considered infringing on Sheets'. Justice Field dissented from this decision, arguing that although there may have been some differences between the two works, it did not change the fact that much of what made up Selden's bookkeeping system had already been established in Sheet's original work. He argued further that allowing such copying would set a dangerous precedent where authors could copy others' ideas without consequence or recompense for their labor and creativity.