Baker v. Selden, 101 U.S. 99 (1879), was a leading Supreme Court of the United States copyright case cited to explain the idea-expression dichotomy. The court held that a book did not give an author the right to exclude others from practicing what was described in the book, only right to exclude reproduction of the material in the book. Exclusive rights to a "useful art" described in a book was only available by patent. Background In 1859, Charles Selden obtained copyright in a book he wrote called Selden's Condensed Ledger, or Book-keeping Simplified. In it the book described an improved system of book-keeping. The books contained about twenty pages of primarily book-keeping forms and only about 650 words. In addition, the books contained examples and an introduction. In the following years Selden made several other books, improving on the initial system. In total, Selden wrote six books, though, evidence suggests that they were really six editions of the same book. Selden, however, was unsuccessful in selling his books. He originally believed he could sell his system to several counties and the United States Department of the Treasury. Those sales never happened. Selden was forced to assign his interest—an interest that apparently was returned to his wife after his death in 1871. In 1867, W.C.M. Baker produced a book describing a very similar system. Unlike Selden, Baker was more successful at selling his book–selling it to some 40 counties within five years. Selden's widow, Elizabeth Selden, hired an attorney, Samuel S. Fisher, a former Commissioner of Patents. In 1872, Fisher filed suit against Baker for copyright infringement. Procedural history The District Court of Southern Ohio held that Baker's books were "in large and material part identical with and infringements of the books of Selden system". The court ordered a permanent injunction to stop Baker from "publication, sale, or otherwise disposing of his book." The Circuit Court affirmed. On appeal to the Supreme Court of the United States, Baker's counsel argued that Selden's work was not appropriate subject matter for copyright. Opinion of the Court The court opinion, authored by Justice Joseph P. Bradley, held that a book did not give an author the right to exclude others from practicing what was described in the book: [W]hilst no one has a right to print or publish his book, or any material part thereof, as a book intended to convey instruction in the