The document discusses the University of Sussex Library's experience with patron-driven acquisition (PDA) of e-books. It shows that PDA purchases have increased as a percentage of the library's book and e-book budget each year since 2010. The library has tackled issues like suppliers, budgets, usage data, and staff awareness of PDA. Going forward, the library aims to use PDA to address interlibrary loans, missing items, and purchasing extra copies of popular reserve titles. Usage data shows heavy use of PDA e-books, especially by undergraduates, with over 17,000 free browses of titles not owned.