This is a privacy lock that does not have the key, but the deadbolt works fine.  The keeper has two compartments to receiver both the deadbolt and door latch.

The one doorknob and  scrolled brass plate are attached as one piece, and that gets attached to the door on one side.  The lockset is attached to the other side, with the shaft fed through the door into the opposing doorknob.

This is a beautiful high end lockset, and I have seen similar sets easily cost over $500 . The lockset looks to be cast metal.  I couldn't see a maker's mark, though there is a etching that reads "2C??" as shown.  

Regardless, this is an elegant piece befitting a lovely door.

The lockset box measures approx 4x6, and all the pieces shown weigh in at a hefty 3.75lbs.

No screws or key are provided.  There are pictures from every angle to show you what a quality set this is.

Priced to sell!  Thanks for looking.