Overview
Windows 7 introduces a new concept of a library, a new entry point for user data. Users can easily find and manage their data in the form of collection data, and this data may be in several different locations on the computer. This library replaces the inherent folders in earlier versions of Windows (for example, My Documents, pictures, music) and puts them in the main "storage". The shell Library API, which provides an easy way for an application to interoperate with the library. Applications can create, interact, and support the library as a level element in their environment.
In Windows 7, the concept of the Shell library is to try to solve the problem of users storing data everywhere on their PCs by allowing them full control over their document library folder structure. In other words, in Windows 7, users can define which folder to store in a document library. We can also say that the shell library is a user-defined, logical collection of folders that represent user data. The folder contained in the library is actually where the user tells windows where his or her important data is stored. The system then indexes these folders for faster query retrieval and richer view presentation capabilities in Windows Explorer based on file attributes and metadata.
In earlier versions of Windows, each application had its own property library. For example, Windows Media player has a different set of scopes than itunes, and neither is consistent with the music folder. Using the Shell Library API, the application can define and work with the user-defined area.
Legend 1
Library L consolidated with Windows Shel
You can also include network folders in the Shell library. This feature will give users a good user experience, both at home and in the organization. Whenever a user opens a file dialog box, he can get a view of the collection that is pointed to by all available libraries.
Note: For more information, refer to Inside Windows 7:introducing libraries.