"It was this early importation and your ability to survive that has placed your race in such demand. It is unfortunate, perhaps, that your species cannot reproduce on our world, but the inhibitors we use to regulate our numbers also affect yours. Naturally, we can't risk a population explosion merely to reproduce your race. So we obtain more of you when necessary." "Why?" "Consider for a moment what might be valuable in a civilization that has no basic needs." "Luxuries?" "Precisely. As an ancillary system operator, I supply a luxury item to my fellow citizens. One that cannot be readily produced by our techniques. I said I was a mardak, but you never asked what it meant. You assumed it was a title. It is, but it's professional, not social. There are no classes on Hel, merely occupations." "All right," Miss Twilley said reluctantly, "What is a mardak?" "The closest analogy in your society," Lyf said, "is a dairyman." THE END