How can I fix my kitchen drawers to keep them from coming apart?

All of my kitchen cabinet drawers keep coming apart. The front cover wants to pull away from the sides and bottoms. They are held together with long ago worn out tacks. The sides appear too thin to screw them. I assume I'll need to use a glue and new tacks, but which glue? Also, the bottoms slide freely and aren't glued in. Should they stay like this?