The Art of Retail Selling
It is a mistaken idea that the skillful salesperson is one who leads a customer around by the nose and empties his pocketbook for him. The days of 'clever' selling are on the wane... What the skillful salesperson does is to build confidence by qualities that radiate helpfulness, giving clear ideas about the article itself, through an expert knowledge of it, at these points in the sale where the customer's mind needs the aid to reach a decision.
The Art of Retail Selling: A Textbook for Sales People,
New York: New York Institute of Mercantile Training, 1909.