missing a switch

I just moved into this house and, to say the least, someone was creative with the wiring. There was a missing overhead light in the living room, I finally put up a new light, and low and behold, there is no switch to turn it off. Other than removing the light and replacing it with one I turn off and on at the source, is there any way to 'add' a switch? A little investigation on my part found an outlet, in another room, that is on the same curcuit.

WHEN YOU SAY AN OUTLET IN AN OTHER ROOM WHAT DO YOU MEAN.