I have an older secretary desk, not antique. The side rails of the drop down front have loosened and slip along the front panel. I'm thinking of applying a bit of glue at one edge of the rails to stop the sliding. Would you recommend this? If so, should I use cyanide glue ?

Sounds like a breadboard type of construction. If that's the case, I wouldn't put glue along the entire joint. I'd glue a small spot mid way between the ends. That would hold the board from sliding and still allow for seasonal expansion/contraction.

Hope you mean cyanoacrylate, not cyanide

 

Definitely the cyanoacrylate Keith.I figured someone would get the idea what I was talking about. Not looking to start a permanent sleep.