Libraries is a cool new feature in Windows 7 that helps you find and manage all of your documents, music, pictures and videos in one location, no matter what location there in. This video from Microsoft outlines the usage of this new feature.
Libraries make it easier to find, work with, and organize files scattered across your PC or network. A library brings your stuff together in one place—no matter where it's actually stored. The result? You get more done.
Say you're assembling a family album from snapshots stashed on an external hard drive, your spouse's PC, and your work laptop. In the past, hunting down specific shots would've been a chore. In Windows 7, you simply create a library, name it something (perhaps, "Family Photos"), and then tell Windows which far-flung folders your new library should include. Your photos are still physically located in three different spots—but now they show up in a single window.
Windows 7 comes with libraries for documents, music, pictures, and videos. But you can personalize these, or create your own, with just a few clicks. There's more. You can also quickly sort and shuffle your libraries—for example, documents by type, pictures by date taken, or music by genre. And easily share libraries with people on a home network.