PS:
I used narrow (5 1/2") boards for the shelves.
It looks more like a floating wall of books, than like a bookshelf.
I installed deeper "standards" in a bedroom (whole wall - floor to ceiling), but didn't like the look and changed it up to the narrow 5 1/2" version.
Larger books go in the deeper more traditional closed back shelves and huge format books get stacked on top of the 3' high shelves.
DeKay
I used narrow (5 1/2") boards for the shelves.
It looks more like a floating wall of books, than like a bookshelf.
I installed deeper "standards" in a bedroom (whole wall - floor to ceiling), but didn't like the look and changed it up to the narrow 5 1/2" version.
Larger books go in the deeper more traditional closed back shelves and huge format books get stacked on top of the 3' high shelves.
DeKay