The document discusses three key challenges of organizational design: balancing differentiation and integration, balancing centralization and decentralization, and balancing standardization and mutual adjustment. It focuses on differentiation and integration, explaining that differentiation is how tasks and roles are structured, while integration coordinates different tasks and roles. There are several mechanisms for integration, such as hierarchies, direct contact between managers, liaison roles, task forces, teams, and integrating roles/departments. The goal is achieving the right balance of differentiation and integration.