New technologies such as the VCR and Google Book Search can change the way copyrighted works are used, thereby making their innovators rich. Copyright owners are aware of these riches and often strategically sue the technology companies with the aim of gaining a share of the money. This dynamic—an innovator investing to create a new technology and a creator of a copyrighted work then suing for her share of the profits—creates an investment incentive problem. The dual goal of promoting the efficient creation of both new copyrighted works and new technologies that augment those works requires us to choose a legal rule that divides the gains from these new technologies between authors and innovators. The fair use doctrine—the statutory rule that allows some types of copyright infringement—is the legal rule that is used to do this dividing. However, economic theories of copyright law do not contain an analysis of investment incentives. This Note analyzes the effects fair use has on the incentives to create copyrighted works and to invest in technologies that affect those works.