art, any person may practice and use the art itself which he has described and illustrated therein. ... The copyright of a book on book-keeping cannot secure the exclusive right to make, sell, and use account books prepared upon the plan set forth in such a book. The court wrote extensively about the distinction between patent law and copyright law. Exclusive rights to the "useful art" described in a book was only available by patent. The description itself was protectable by copyright. In this sense, the Court clarified Selden merely held a copyright, not a patent. The conclusion to which we have come is, that blank account-books are not the subject of copyright; and that the mere copyright of Selden's book did not confer upon him the exclusive right to make and use account-books, ruled and arranged as designated by him and described and illustrated in said book. The Court reversed the ruling of the Circuit Court. The decree of the Circuit Court must be reversed, and the cause remanded with instructions to dismiss the complainant's bill. Subsequent developments The principal holding of Baker v. Selden is codified in §102(b) of the Copyright Act of 1976. Baker is still heavily cited today, with more than 130 decisions citing it from 1984–2004. Although Baker v. Selden sharpened the idea-expression dichotomy, Pam Samuelson argues Baker is not the genesis of the distinction nor of the “merger” doctrine ("which holds that if an idea can only be expressed in one or a small number of ways, copyright law will not protect the expression because it has “merged” with the idea"). References External links Copy of Selden's Condensed Ledger, the work at issue in the case, from the Library of Congress; available as a series of images or in PDF format United States copyright case law United States Supreme Court cases United States Supreme Court cases of the Waite Court 1879 in United States case law