The dictionary defines a hierarchy as a graded or a ranked series in which objects are above, below, or equivalent to one another. This definition readily applies to most human systems from business to religion to government. The military organization of the U.S. Army represents one of the more rigid examples of a hierarchical organization. From higher-level national command structures through basic unit building blocks, the army culturally, traditionally, and legally has maintained a chain-of-command organizational structure throughout its many historical changes. Gaining a clear understanding of the army as a military organization requires an understanding of its mission, command structure, the current modular transformation, how the organization as a whole is managed, and its component units. This entry discusses the organizational structure, mission, and ...