This ebook based on papers from the 9th Northumbria International Conference on Performance Measurement in Libraries and Information Services reflects the international nature of the effort to elicit and define effective value measurement, and demonstrates the attention now being given to this area of assessment by libraries. The papers selected from the conference reflect the desire by researchers and practitioners to explore perceptions of value. The contributions are mainly focused on the academic context, but the consideration of value is important in any sector, and the fundamental value of libraries in all sectors will be reinforced by the development of convincing tools and methods to assess library value. A range of new and different evidence is presented in these papers which will help to define library value and impact.