Courier

The messenger sells his body to others; he sells the strength of his legs, the volume of his lungs, and the knowledge in his brain to move the package, the letters, the airplane tickets, the subpoena, to where it needs to be, when it needs to be there. He is paid for speed and distance, for his ability to move about an urban environment faster than the motorists around him.

He does this on some of the simplest technology: the bicycle. A more fuel-efficient mode of transportation has not been found.

The messenger.