Though this technique is used for that purpose, it is also used to exaggerate. HDR allows for a greater dynamic range of luminance between the dark and light areas of a photograph. By taking at least 3 of the same photos at different exposures (by bracketing) then going into photoshop (or other programs) and layering the images together.
If you think you need a tripod for this technique you are wrong. The photo's below where done without a tripod.
(if you look closely at the leaf in the left corner of all 3 pictures you can see that I didn't hold the camera perfectly still)
By tone mapping these 3 images together:
|-1 stop exposure|
|+1 stop exposure|
|Final HDR Image|