Management can be viewed as an art, science, or profession. As an art, management relies on theoretical knowledge and creativity in personalized application. As a science, management is based on systematic experimentation and principles with universal validity. As a profession, management involves a well-defined body of knowledge, restricted entry requirements, ethical standards, and service to others. Management consists of three levels - top, middle, and lower. The top level integrates activities, the middle level ensures policies and resources, and the lower level implements policies. The main functions of management are planning, organizing, staffing, directing, and controlling.