Cowboy boots and sales book

A friend of mine wants me to read a sales book, but he can't remember the name of it. He says that in it, the author tells a story of how he was selling servers to a potential client. As part of the process, he gave him a shoe box with one cowboy boot in it. He held on to the other boot. Then he said that he told the potential client that if they made the right decision, he would give them the other boot.

I'm not saying this tactic will or won't work, but I am interested in reading the book. Any help in finding this book would be greatly appreciated.