A man walked into a Chicago building and sent up a note. It was rude. It was also the best sales pitch in advertising history.

The gist: You don't know what advertising is. Nobody here does. I do. Send the messenger back if you want to hear it.

That man was John E. Kennedy. And what he said next still decides whether your copy works.

First, a warning about the story

This tale gets retold a lot, and the retellings don't match.

One version puts the date in May 1904. Another says May 1905. One has the note going to Lord & Thomas partner A. L. Thomas, who hands it to young Albert Lasker. Another says Lasker read it himself. In one, Kennedy waits in the lobby. In another, he's in the saloon downstairs.

So treat the details as lore. What every version agrees on is the core: an ex-Canadian Mountie, a note, a long night with Lasker, and three words.

The Mountie with an idea

Kennedy had served in the Canadian North-West Mounted Police before he got into advertising. He told Lasker he'd spent long, lonely nights in the snowy north thinking about one question. What is the one thing that makes advertising work?

His answer to Lasker was salesmanship in print.

That's the big idea. An ad is a salesperson, just not a person. It has no face, no handshake, and no second try. It has to do the whole job with words on paper.

Why three words changed the job

Think of a store clerk who only stood at the door and shouted the shop's name. Fired by lunch. (That's my picture, not Kennedy's.) A print ad that only says who it is does the same thing.

A good salesperson does other things. They figure out who they're talking to. They give a reason to buy. They answer the doubt in your face. And they ask for the sale.

Kennedy is also tied to "reason why" advertising. Give the reader the reasons. Prove the claim. Don't just say you're good.

The chapter titles of his 1905 articles read like a to-do list: "You Must Do the Sum to Prove It" and "To Whom Are You Advertising?"

The night that built a copy department

Per the Scientific Advertising site, the two men talked until about 3 in the morning. Lasker walked out with his answer.

Lasker then hired Kennedy. The same source says Kennedy became the highest paid writer in advertising. Kennedy's first job was to write down his principles so the agency's other writers could learn them.

That was a new idea too. Teach copywriting to a room full of people. The International Business Hall of Fame's bio of Lasker says he hired young newspapermen and trained them in Kennedy's approach, and calls it the first systematically trained copywriting staff in America.

Later, Lasker said it plainly to his staff in 1925, as quoted on the Scientific Advertising site: "It was that in 1905 when Kennedy told it; it was that before anyone had ever told me, and it will always be that, and nothing else."

He also said the history of advertising couldn't be written without giving Kennedy first place, because every copywriter was guided by his principles. That one is quoted on Wikipedia from a secondary source, so take it as reported.

Where the idea gets lost

You've seen it. A commercial you love, and you can't say what it was selling. That ad forgot Kennedy.

The test is rude, like his note. Imagine the same words coming out of a person at a door. Would they get the sale, or just a chuckle and a closed door?

The quiet turn

The reader is a person with a question and no time. Every line either answers it or wastes it.

That's a good rule for writing, and honestly for most conversations.

Put your copy behind the counter

Give the reason why. For each claim ("fast," "better," "easy"), add the reason it's true. A number. A test. A fact.

Name one reader. Write down who this is for before you write a word. Kennedy's own chapter title asked it: To whom are you advertising?

Ask for the sale. End with one clear next step. A salesperson who never asks gets a nice chat and no order.