Social work has an impact on large numbers of citizens through its services for children and families, elderly people, those with mental or physical health problems and offenders. It also provokes much criticism; its effectiveness is questioned and there are increasing demands for this to be demonstrated. This text discusses how this task may be tackled and explores possibilities for evaluative research in contexts which are often not considered feasible for such enquiry. Paying particular attention to the diverse and complex functions of social work, the book reviews the implications for choosing and adapting research methodologies, emphasizes the importance of identifying the process of social work as well as its outcomes and distinguishes between the identification of effectiveness and its evaluation. It also describes the various means of dissemination which are necessary if research is to influence policy and practice. The book, which gives many examples of research in action, draws on evaluative research in Britain and the US and also on the experience of the Social Work Research Centre. It has been written for researchers, managers, practitioners and students with responsibilities to undertake or to understand the systematic evaluation of social work.