While I agree with Steve and Henry on the best way to go about the task, let me suggest an alternative 'experiment' that you may want to try ... and if the experiment does not work, then you will need to strip the paper and do as Steve and Henry suggested. From your description of the age of the wallpaper, I will assume that it is paper and not a vinyl-coated wallpaper. If it is not paper, then forget about the experiment and go straight to what Steve and Henry told you. If the wallcovering is paper, though, why not try an experiment on a 4 foot x 8 foot section of the wall? First, clean the wall thoroughly with a sponge and a solution of TSP (trisodium phosphate) that you can probably get at your paint supply store or a well-stocked home center. The reason for the TSP wash is to try and get the surface cleasn of all the accumulated cooking vapors, tobacco smoke, and whatever other airborn stuff that now coats the surface of the wallpaper. When the test portion is cleaned and dry, paint it with a top-quality primer. KILZ makes one, and so does Sherwin Williams and most paint manufacturers. IF the TSP washing did not cause the old wallpaper to disengage from the wallboard, and IF the primer did not cause the wallpaper to slough off the wall, then you might say a couple of Hail Mary's and paint over the primer with your intended top coat paint. IF this experiment works on your test section, then you might try to extend it to another section, and go section-by-section, to see if it may work for the entire wall area that you want to cover. Let me finish this reply by telling you, again, that I suspect that the experiment will not work, and that you will need to strip the paper from the wall ... but, being an experimentalist by nature, there is no harm in trying the unconventional approach. We all learn from our mistakes. Good luck, and do proceed cautiously.