How do I open a wood desk drawer?

Question

I have an old wooden roll-top desk. Until last week, all drawers opened fine. Suddenly, they are all 'locked' except the middle pull-out drawer. I recall as a child being told there was a 'secret' to opening these old desks when this happened. I tried pushing and pulling the center drawer in and out to no avail. Is there a secret 'button' somewhere? I have looked all around the desk but don't see one. Please help I have some valuable papers in there.

Answer 1

try to use a straight bladed knife and slide it along the gap as you jiggle the key

Answer 2

It might have a secret lock, but I am wondering if humidity has done it.  Has it been very humid where you live?  If you don't have air conditioning (which cools plus dehumidifies), this sultry weather can certainly cause drawers to stick.