The object of this article is to endeavor to ascertain the nature of the property interest involved in the word copyright. Copyright law is usually treated as an offshoot of patent law-as one of the two queer branches of our jurisprudence in which, by an exception depending on statute, intangible ideas are protected. The dissimilarities are more pronounced than the similarities. One gives a monopoly; the other merely a prohibition against copying-a very different thing. About the only similarity is that both deal with intangible rights against all the world but that is an element which they share with several other branches of the law. They do not even share a common origin in statute rather than custom for it is still debatable whether the original copyright statute-the Statute of Anne '-created a new right or merely limited a pre-existing common-law copyright.2 The most striking feature of copyright is that it is the only branch of the law which contemplates, at least in a normal state of affairs, the existence at the same time of two valid titles to the same piece of property. That is not true of patents. Both these branches of the law start with the proposition that to obtain a valid title to the property which he claims, the author or inventor must have originated it, but in copyright law the word originate is used in a strictly Pickwickian sense. It means, in copyright, that the author thought of what he seeks to have protected all by himself; not that he was the first to think of it.3 The work must be original with the author but it need not be original to the world. The validity of a copyright to a musical figure, for example, is not impaired merely because the same figure is