What is an organization? What is a manager? Why do organizations need managers?
An organization is a collection of people working together to achieve a common purpose. A manager is a person in an organization who supports and is responsible for the work performance of one or more other persons. Every manager’s job includes the responsibility of helping other people to achieve high performance. Without this help, the efforts of the organization’s members probably would not be coordinated sufficiently to achieve the organization’s common purpose.
Source: Management, 11th Edition - John R. Schermerhorn