Patron-Driven Acquisitions (PDA) is a new model used for e-book acquisition by academic libraries. A key component of this model is to make records of ebooks available in a library catalog and let actual patron usage decide whether or not an item is purchased. However, there has been a lack of research examining the role of the library catalog as a tool for e-book discovery and use in PDA. This paper presents a case study of using PDA for e-book acquisition in an academic library, with a focus on the role of the library catalog in this purchasing model. The implications and challenges are also discussed.