This is a very useful tool which is built into Vista, when you are working on a file shadow copies of the file are made. This is useful when you are working on a file, document, or image and you save the changes made to it. Usually when you make the changes they are permanent but with Vista you can right click on the file and navigate to the “Previous Versions” tab and see which version you would like to restore.

This feature is available for individual files or directories, but this feature is only available in Vista Ultimate, Vista Enterprise, and Vista Business. So the Shadow Copy is a very useful feature which can only be used with these versions of Vista.

Link: Lifehacker