Read the link for yourself. Anyone who does woodworking will be familiar with these. For the uninformed, this jigs places pocket screws for you, which is a strong method of connecting two pieces of wood. In addition to this, it tends to hide the screws (if you place them correctly).
If you build your own wooden bookcase, you could use one of these. Drill not included.
There is a coupon code for $15 off a $75 order or more. Coupon code is 82010. Go to the home page to see the code yourself.
YES, I know it is advertised as 99, I subtracted the coupon code.