The Londoner

by Michael E. Porter Awareness of the five forces can help a company understand the structure of its industry and stake out a position that is more profitable and less vulnerable to attack. Editor’s Note: In 1979, Harvard Business Review published “How Competitive Forces Shape Strategy” by a young economist and associate professor, Michael E. Porter. It was his first HBR article, and it started a revolution in the strategy field. In subsequent decades, Porter has brought his signature economic rigor to the study of competitive strategy for corporations, regions, nations, and, more recently, health care and philanthropy. “Porter’s five forces” have shaped a generation of academic research and business practice. With prodding and assistance from Harvard Business School Professor Jan Rivkin and longtime colleague Joan Magretta, Porter here reaffirms, updates, and extends the classic work. He also addresses common misunderstandings, provides practical guidance for users of the framework, a