Fair use is one of modern law\u27s most fascinating and troubling doctrines. It is amorphous and vague, and notoriously difficult to apply. It is, at the same time, vitally important in copyright and perhaps the most frequently raised and litigated issue in the law of intellectual property. This article offers a novel theory of fair use that provides both a better understanding of the underlying principles and better tools for applying the doctrine. In contrast with the dominant understanding of fair use in the literature — that fair use addresses market failure — the article proposes viewing fair use as a doctrine that aims at calibrating the allocation of uses among authors and the public. Specifically, fair use allocates directly to user...