ISSUE:
Whether Baker had infringed copyrights held by Selden?
Whether Selden had an exclusive right to the use of the system explained in his book?
RULE:
Idea-Expression Dichotomy: A copyright can be obtained only over a particular expression of an idea, it does not protect the idea that underlies that expression and this is what limits copyrights and differentiates it from patents. An idea/art/method can be patented whereas the expression of an idea/art/method can be copyrighted.