This paper provides guidelines for conducting and reporting case studies in software engineering, emphasizing the importance of understanding contemporary phenomena in their natural context. The authors, Per Runeson and Martin Höst, draw on their own experience and existing methodology handbooks from social sciences and information systems to offer practical advice. They address the challenges of empirical research in software engineering, where the focus is often on complex, real-life issues involving human interactions with technology. The paper outlines a case study research process, including defining objectives, planning data collection, collecting evidence, analyzing data, and reporting findings. It also discusses ethical considerations and provides checklists for researchers and readers to ensure the quality and validity of case studies. The authors emphasize the need for flexible, iterative approaches that can adapt to the dynamic nature of software engineering projects while maintaining a clear chain of evidence and contributing to existing knowledge.This paper provides guidelines for conducting and reporting case studies in software engineering, emphasizing the importance of understanding contemporary phenomena in their natural context. The authors, Per Runeson and Martin Höst, draw on their own experience and existing methodology handbooks from social sciences and information systems to offer practical advice. They address the challenges of empirical research in software engineering, where the focus is often on complex, real-life issues involving human interactions with technology. The paper outlines a case study research process, including defining objectives, planning data collection, collecting evidence, analyzing data, and reporting findings. It also discusses ethical considerations and provides checklists for researchers and readers to ensure the quality and validity of case studies. The authors emphasize the need for flexible, iterative approaches that can adapt to the dynamic nature of software engineering projects while maintaining a clear chain of evidence and contributing to existing knowledge.