All types of libraries and information services have traditionally collected a range of performance information about service efficiency. What has recently become a challenge for library and information managers is how to obtain information about the effectiveness of services and how to assess the impact of those services on users. Having a full understanding of impact is the key to library service development. Focusing on impact should help in thinking creatively about the service, making the case for resources, enabling sound development planning and enhancing job satisfaction. It can be difficult to get a grip on the rather slippery concept of service impact, but the authors have developed an effective answer. Their rigorously tested evidence-based approach helps LIS managers to work through a structured process of impact evaluation linked directly to their own objectives and priorities. The core chapters of the book take managers through this process model for impact assessment, backed by tools and examples to equip them with all that they need to address their own service impact questions. This book is an essential tool for practising library and information service managers and policy makers in the field. It is equally relevant to public, education, health and special libraries and information services, and is also of value to higher education professionals and students.