I have an unfinished attic in my NY house. The attic is bordered on one
(in)side by a bedroom and on part of another (in)side by a bathroom and
hallway. The other part of the attic (crawl space at best) is over the back
patio. The attic space has a small double-hung window at one end (I always
keep it open for ventilation) and a few small round air vents in the patio
ceiling.

The previous owner (can't imagine the original builder doing this) has
placed foil-faced insulation, with the foil facing inside, between all
rafters in th eattic on the underside of the roof. [If I take the insulation
away there is the wood tongue-in-groove roof material and on top of that
just a layer of asphalt roofing shingle]

Does the insulation do anything for me? Is it the correct insulation to
have - foil faced with the foil showing inside?
There is no insulation on the inside walls up against the
bedroom/bathroom/hallway as mentioned above. Do I need and should I put
insulation in between the wall studs here?

Thanks for your help.
Walter