This paper by Richard L. Baskerville explores the use of action research in information systems (IS) research, a method that has gained prominence in the late 1990s. Action research, rooted in post-positivist assumptions, is characterized by its focus on practical problem-solving and interpretive, idiographic research. The paper surveys the historical context, philosophical underpinnings, and various forms of action research, emphasizing its participatory nature. It outlines a five-step model for conducting action research, including diagnosing, action planning, action taking, evaluating, and specifying learning. The paper also discusses the distinction between action research and consulting, highlighting key differences in motivation, commitment, approach, and theoretical foundations. A case study of a semantic database prototyping project is presented to illustrate the application of action research in practice. Finally, the paper addresses the limitations of action research, such as its qualitative nature and ethical considerations, and emphasizes its value in enhancing the relevance and practical impact of IS research.This paper by Richard L. Baskerville explores the use of action research in information systems (IS) research, a method that has gained prominence in the late 1990s. Action research, rooted in post-positivist assumptions, is characterized by its focus on practical problem-solving and interpretive, idiographic research. The paper surveys the historical context, philosophical underpinnings, and various forms of action research, emphasizing its participatory nature. It outlines a five-step model for conducting action research, including diagnosing, action planning, action taking, evaluating, and specifying learning. The paper also discusses the distinction between action research and consulting, highlighting key differences in motivation, commitment, approach, and theoretical foundations. A case study of a semantic database prototyping project is presented to illustrate the application of action research in practice. Finally, the paper addresses the limitations of action research, such as its qualitative nature and ethical considerations, and emphasizes its value in enhancing the relevance and practical impact of IS research.