The concept of the public domain is a powerful rhetorical element in he policy debates involving intellectual property. But is it a stable and useful concept for analyzing information issues? Can the notion of the public domain and the concept of the information commons be separated? Is the notion of the public domain merely another way of expressing the public interest? This paper canvassed the literature, seeking a theoretically consistent definition for public domain that was equally applicable across the copyright, trademark and patent spheres. The analysis demonstrated that there is no such construct. The paper also reviews the findings of those who have tried to empirically demonstrate the ambit of the public domain and illustrates ...