 How does Conrad go back in time?
He'd been a war baby, born of one of the tides of soldiers—enemies and allies, both—that had engulfed the country in successive waves and bought or taken the women. "He's dissatisfied with the current social order and killing you is part of an elaborate plan he's formulated to change it. There was no devastation, no war, no unhappiness, none of the concomitants of normal living. "And Conrad really got upset over the way Earth has been exploiting the not so intelligent life-forms on the other planets," Raymond continued. "We just come a couple of centuries or so later, that's all. We're virtually the same people ... although it is amazing what a difference two hundred odd years of progress and polish can make in a species, isn't it?" And, on those worlds, it's far cheaper to use native labor than to ship out all that expensive machinery. I don't mean in the now for me, but the now for you," Martin explained laboriously. Unaware of the near-contempt in which his young ancestor held him, Raymond went on blandly: "Anyhow, Conrad took it upon himself to feel particularly guilty, because, he decided, if it hadn't been for the fact that our great-grandfather discovered the super-drive, we might never have reached the stars. "Unfortunately, Professor Farkas has just perfected the time transmitter. Conrad's idea had been to go back in time and "eliminate!" In that way, there would be no space-drive, and, hence, the Terrestrials would never get to the other planets and oppress the local aborigines. Conrad got the apparatus built, or perhaps he built it himself. But when it came to the point, Conrad couldn't bear the idea of eliminating our great-grandfather—because our great-grandfather was such a good man, you know." "So Conrad decided to go further back still and get rid of his great-grandfather's father—who'd been, by all accounts, a pretty worthless character." "I wormed the whole thing out of him and all of us—the other cousins and me—held a council of war, as it were, and we decided it was our moral duty to go back in time ourselves and protect you." Induced , Martin knew, could have meant anything from blackmail to the use of the iron maiden. "Then we were all ready to forestall Conrad.
 Conrad built a time transmitter using a copy of Professor Farkas' plans.
 Conrad stole Professor Farkas' time transmitter to send himself back in time.  Professor Farkas sent him back in time with the time transmitter.  Conrad built a time transmitter using a copy of Professor Farkas' plans.  Professor Farkas' assistant sent Conrad back in time using the time transmitter after Conrad gave him a bribe.