In Feist Publications, Inc. v. Rural Telephone Service Co. 499 US 340 (1991) the United States Supreme Court held that copyright does not extend to a mere compilation of facts.  In this case, it was a telephone directory much the same as the one in ProCD v. Zeidenberg 86 F.3d 1447 (7th Cir. 1996). Furthermore, the Court also ruled that something more than simple "sweat of the brow" labor was required before copyright protection would ensue, with some modicum of authorial originality necessary.  Accordingly, it was held in Feist that copyright did not extend to a telephone directory, no matter how laborious a task its compilation was.  The decision in ProCD v. Zeidenberg 86 F. 3d 1447 (7th Cir. 1996) is highly significant, therefore, in that it permits copyright or quasi-copyright protection to be extended to non-copyrightable material through the use of contract.