At the top of the wall? How will you access the books and what is going on the bottom under the shelves I am confused as to what you are asking. Maybe a drawing to show us what you are planning.

They’ll be accessible by a rolling library ladder, and I’ll hang art underneath.

Sorry my question is confusing. I’m asking whether the length of the shelves should run the full length of the wall, so 12ft long, or if I should leave a few inches at either end of each shelf so there’s some space before the end of the wall.

Won't the ladder get in the way of the walkway past it? I think I would put the shelves low for the books and art over it.

I don’t think so, the walkway is pretty wide and the rolling ladders don’t stick out too far. But something to think about, thanks!