I nodded. Reactions by their very nature are not always appropriate, and I had invested a lot of emotional capital in a heavy-duty set. So, "Okay, I know more about them than the school kids," I said.

"Thanks. That can be our point of departure." He took a sip of coffee. "My own background is in law and accounting, followed by the military, military intelligence, and civil service, in that order. Then I got into this business. What technical stuff I know I've picked up along the way, a scrap here, a crash course there. I know a lot about what things can do, not so much about how they work. I did not understand the details on this one, so I want you to start at the top and explain things to me, for as far as you can go. I need the background review, and if you are able to furnish it I will also know that you are the man for the job. You can begin by telling me how the early space-exploration robots worked, like, say the ones they used on Venus."

"That's not computers," I said, "and for that matter, they weren't really robots. They were telefactoring devices."

"Tell me what makes the difference."

"A robot is a machine which carries out certain operations in accordance with a program of instructions. A telefactor is a slave machine operated by remote control The telefactor functions in a feedback situation with its operator. Depending on how sophisticated you want to get, the links can be audiovisual, kinesthetic, tactile, even olfactory. The more you want to go in this direction, the more anthropomorphic you get in the thing's design.

"In the case of Venus, if I recall correctly, the human operator in orbit wore an exoskeleton which controlled the movements of the body, legs, arms, and hands of the device on the surface below, receiving motion and force feedback through a system of airjet transducers. He had on a helmet controlling the slave device's television camera, set, obviously enough, in its turret, which filled his field