Here's how to use the History tool (Show step-by-step instructions including before-and-after examples--include your name so I know who gets credit):

Here are examples of student projects using this tool:

(see Filter Projects)
Here are the steps of the History Brush:
1. Have a photo ready to use your tool on
2. Click the History Brush Tool on the left, right under the brush and pencil tool
3. Click Filter and filter your picture by choosing one of the different types of filters (sharpen, texture, blur etc.)
4. After filtering go to your history and click on the little box in the paste box, after clicking the history brush tool
should appear in the box.
5. Then go back to your drawing and paint over what ever part of your picture you want to be unfiltered, make sure you dont unfilter
all of your picture so that theres a difference in the picture
Gaby claimes this

GABYS EXAMPLES OF THE HISTORY BRUSH TOOL:

history_brush_final.jpg
heart_earth_final.jpg