What is Type Library and its purpose?
Type libraries are files that explicitly describe some or all of the contents of components. This includes information about the methods properties constants and other members exposed by the component. Development tools such as Visual Basic make use of the information contained in the type library to help you as a developer access and use the component. In addition type libraries provide a convenient way to include a simple level of descriptive documentation for component members. You can use them through ‘Tools –> References’ in VBE.