How the Batsuit Works
An anonymous reader writes "Batman's outfit plays a much more prominent role in Batman Begins than it did in the previous films. And a lot of the technology actually seems plausible. This HowStuffWorks article explains all its features."
In modern DC Comics lore, Superman gave Batman a chunk of kryptonite after a nasty fight with a villain (I think it was Brainiac) who managed to control Superman's mind. The logic behind it was that in case a situation like that ever happened again and he needed to be taken down, Superman wanted his most trusted ally to have a trump card to stop him from doing evil. Batman's the man he trusted most to both keep it safe from the hands of other villains, and not to be tempted to use it unless it was an absolute emergency.