In previous versions of Windows, users managed files by organizing them in different folders and sub folders. In Windows 7, libraries can be used to organize and access files regardless of where they're stored.
A library gathers files from different locations (different folders, computers, hard drives) and displays them as a single collection, without moving them from where they're stored.
There are four default libraries (Documents, Music, Pictures, and Videos). Users can also create new libraries or modify existing ones to suit their needs and share them with people in your Home Group. Within a library items can be ordered by folder, date and other user-chosen properties.