Luther Gulick and Lyndall Urwick were influential classical thinkers in administrative theory. They worked closely together and were influenced by Taylor's scientific management ideas and military experience. Gulick focused on public administration as a professor and administrator, while Urwick founded a management consultancy. Together, they developed administrative theory principles related to organizational structure, coordination, and management. Their work built upon Taylor and Fayol and emphasized the importance of formal organization and structure. While influential, their theories also received criticism for weaknesses and duplication.