The Salesman is the owner of rather scary books who only appeared in the 1945 animated short, Duck Pimples.
Role in the short
Donald has a scary and unpleasant evening, until a shady-looking book Salesman appears at his door. Soon after, he disappears, leaving him with a collection of "whodunnit?" novels. He is not seen again after this scene.
Other Appearances
The Salesman also appears in Mickey's 60th Birthday, where he arrives at Donald's house, to arrest him on the charge of abducting Mickey Mouse, who is under a spell, so others do not recognize him, until he finds his own magic.