The document discusses the nature and structure of local governments. It defines local governments as subordinate political entities that are territorial subdivisions of a higher national authority. Local governments have legal authority to provide services to their constituents. They exist in hierarchical layers and are constituted as municipal corporations. The rationale for local governments is that they promote welfare by providing services at a community level. The document outlines different systems of classifying local government structures internationally and describes the structures and services of local government units in the Philippines.