Early authors in the field of public administration described differences between public and private employees and concerns over motivating public sector employees. Paul Van Riper described the issue in his 1952 history of the U.S. civil service system. Even Woodrow Wilson's seminal 1882 essay that founded the field of public administration expressed concern over the performance of civil servants. Much of Max Weber's work on bureaucracy focused on similar issues.[1] Kaufman's The Forest Ranger introduced the idea of an organizational culture unique to government employees in the 1960s, which contributed significantly to the field of study.