floor-to-ceiling built-in shelves to provide storage for books and display space for collections, as in this home office. A library ladder runs on a track around the perimeter of the room to provide access to books on high shelves.
Maybe this in the basement but instead of a window a fireplace with a seat. Frame a window seat with built-in bookshelves. Now books are just an arm's length away when homeowners want to curl up on the window seat.