Abstract: Digital libraries depend on user interfaces as surrogates for reference librarians and the physical cues in library architectures. Dynamic, multi-faceted user interfaces are thus crucial to the success of high-volume digital libraries. Our approach to building and testing interfaces using a framework of 'agile views' will be illustrated using the Open Video Project. The Open Video Project (www.open-video.org) aims to create and open source digital library of digital video for researchers, students, and the public, serve as a testbed for building interactive user interfaces and an environment for building a theory of human information interaction. The digital library has been is used by educators and researchers around the world, is an Open Archives Initiative provider, and collaborates with several institutions including CMU, NASA, and the Internet Archive. In addition to the issues of operating a digital library, we focus on designing usable visual surrogates and conducting user studies for these designs. These studies have led to an evaluation framework and a set of measures for assessing how people make sense of video. This talk will provide an overview of the design framework, challenges of sustaining a digital video library, and our evaluation framework.