The document summarizes several theories of the firm, including:
1. Transaction cost theory explains why firms exist to minimize costs of exchanging resources internally and externally. Costs arise when transferring products between stages.
2. Agency theory describes the relationship between a principal delegating work to an agent, and how conflicts can arise from differing interests.
3. Growth theory examines how firms grow through internal expansion or external mergers and acquisitions, and the conflict between managers and shareholders.
4. Knowledge-based theory views knowledge as the most important resource for firms, and emphasizes organizational learning and knowledge sharing strategies.