I actually remember this one. It was how I learned the Winston song.
Chesterfield must of been one of the last companies to introduce filter tips. Filters were brought in to reduce or "filter out" the tars. It was the tobacco companies way of addressing the growing awareness that smoking might be bad for you. Of course according to this ad Chesterfield was the first company to get them right.
I was a always big fan of Wilson Bryan Key's theories of subliminal advertising and implanted messaging. I think I still have a foil hat with his name on it. But even ignoring the fact that their brand name was Kool, this ad looks packed.