The combined influence of rapidly changing technology and the economic downturn has forced librarians and publishers to reassess their respective roles in the delivery of information. Many are realizing that the costs of traditional collection management through journal subscriptions and particularly the 'Big Deal' are not only burdensome but unsustainable. The result of these forces will likely be continuing diversification in access models, with institutions acquiring content through subscriptions, aggregators, demand driven acquisition, document delivery, and repositories. Increased complexity in business models and the high cost of information, will bring increasing need for careful evaluation and analysis of financial efficiencies. The obvious place for such analysis to occur is in the Library. Demand Driven Acquisition offers inherent cost savings for libraries, as the library only pays for the content that is read. In this session, we will describe a trial of a demand driven service, designed by the technology company Labtiva, and executed in partnership between the University of Utah and Nature publishing Group. The goals of the project are to provide instantaneous access to content for patrons, while providing the means for just-in-time delivery, at a reduced cost per usage.