This document discusses patron-driven acquisitions (PDA) from the perspective of a university library. It outlines two broad categories of library collections, and how libraries traditionally build collections by guessing what patrons want. The document then introduces PDA as an alternative model, where libraries expose ebooks and only purchase titles when patrons access them. It provides examples of the University of Utah's experiments with PDA, and discusses problems with budget management, content availability, and metadata quality. Finally, it predicts that future acquisitions will involve less mediation by librarians and more "just in time" purchasing driven directly by patron use.