For calls that use late binding, as you may recall, a type library reference is not required. In this situation, VB uses another Registry entry called an AppID. An AppID is stored in the Registry using the same human readable name that is used with the CreateObject and GetObject calls, for example Excel.Application is the AppID for the Excel Application root object. This AppID entry in the Registry is just another layer of indirection that allows the client to look up the ClassID of the component by referencing a more friendly name