According to this answer to what the moon is made of, the moon's crust is, among other things, 43% oxygen.
Assuming we were to go back to the moon within the next couple of years with the goal of establishing a long-term presence (read: base/colony), would we be able to process the crust and extract that oxygen to let our astronauts breathe without having to bring all of the atmosphere they'd otherwise need along on the journey?
More to the point, is it worth it to bring the equipment needed to extract oxygen out of the moon's crust, or would it be easier/more cost effective to just fly in a bunch of air in compressed tanks?
Note: Obviously oxygen isn't all we need, as Apollo 1 tragically proved, but if we can get even a part of the air needed to fill a base with as we build it, that could save considerable mass (and, thus, cost) needed to be brought in -- unless the equipment necessary weighs more and/or is more costly to operate, of course.