Experts disagree about the division of labor between direct marketing and sales. But Uarco figured it out 80 years ago.

“The direct mail does the telling and the salesman does the selling,” wrote Direct Mail Selling, a short-lived trade publication, in a 1929 article on the firm.

Uarco sold business forms systems, mostly through its sales force, but it needed a better return on investment. Unable to reduce its manufacturing costs, it decided to economize on sales travel (no small thing in an era when salesmen traveled by train).

So it sent a four-part mailing to 72,500 prospects. The goal? To generate leads and qualify them. But that meant “stealing the salesman’s story,” according to Direct Mail Selling.

The first piece, a four-page, three-color broadside, explained the savings and other benefits. The second included a business chart, showing the systems used by every kind of business. The third and fourth mailings were equally detailed.

All four mailers featured testimonials, and all offered a customized system planning book. All the reader had to do was fill out a return postcard—he soon got a handsome volume with his name hand-lettered on the cover.

As reported by Direct Mail Selling, the campaign pulled 5,500 inquiries at a cost per lead of less than $2. And they were good leads—14.5% converted right away, producing $78,000 worth of new business. All the salesman had to do was show up.

Another 34.2% were deemed good prospects—they needed handholding and a closing call. And 36.1% were considered fair—the salesman had to do “a thorough and detailed telling, selling and closing job.” Only 15.2% were rated “no good.”

“One thing is certain,” Direct Mail Selling wrote. “After a prospect has read these four mailings, which tell the whole story of the Uarco business systems, he does not mail in an inquiry out of curiosity.”

The conclusion? “Direct mail can never use enough sales arguments and tell these in enough detail.”

The same could be said of email. Are you selling a complicated product or service? Don’t stint on the particulars. They can go in the message, or on a Web landing page. But forget the shibboleths about long copy. As a master direct marketer recently said, “There’s no such thing as long copy—only boring copy.”