This Fourth Northumbria International Conference on Performance Measurement in Libraries and Information Services centered on the theme of "meaningful measures for emerging realities" and contributors surveyed the field of performance measurement from that perspective. The proceedings begins with seven keynote and invited papers from speakers around the world that provided the framework for the event. The seminar papers from the parallel sessions are arranged within this proceedings under the following headings related to the overall conference theme: Standard/Strategies and Policies; User-Centered Measures; and Assessing the Emerging Environment. Within these broader categories, speakers' perspectives explored a wide array of issues, ranging from report on current significant research projects such as the ARL E-Metrics Initiative and other discussions of measuring the use and extend of a library's electronic offerings; the LibQUAL+ instrument and presentations related to service quality for both internal and external customers; results of user surveys both in print and on the Web; existing and developing standards; measures for information skills instruction; the importance of impact indicators; building a culture of assessment; determining research library support of sponsored research; and designing user-framed services. (AEF)