Even without a bump on the back of the hand, whapping it with a heavy book of any kind is likely to hurt. In this case, the intended goal is to rupture the bump if it's a fluid-filled ganglion cyst.

The traditional "Bible treatment" only works about half the time. More than 50 percent of these cysts come back again. A more successful way to treat it is with needle puncture and aspiration. The doctor inserts a needle into the sac and draws the fluid out. Cure rate is about 85 percent with this method.

Closed rupture (the Bible Treatment) or needle puncture isn't always advised. There is a risk of injury to the arteries or nerves in that area. For some ganglion cysts, surgical removal is the best treatment. When the stalk that connects the cyst to the joint or tendon sheath is removed, the cyst doesn't come back.

You'll need some medical tests first to know for sure what kind of cyst is present and the best way to treat it. It's probably best to thank the grandpa for his offer but choose a more effective, less painful method of treatment.