For King & Country by Robert Asprin, Linda Evans, James Baen Page A

confronted by two possible futures. Two or more. There are people attuned to the future of fractural planes, just as others are attuned to a fractural plane's past. You might think in terms of one set of instruments tuned to ham radio frequencies and another tuned to microwave transmissions. People who have learned to shift their own consciousness from one plane to another—so called astral projection or out-of-body experience—are actually moving the pattern of their consciousness from one plane to another, or to some other referent point on their own plane. What
we've
done is engineer a way to hook the conscious portion of a human mind, which is, after all, merely a pattern of energy which can be codified and transferred from one point to another, through the endless shifting of fractural planes—"
    "Wait, slow down!" Stirling resisted the temptation to massage aching temples.
    Mylonas halted, brows climbing into his receding hairline. "What don't you understand? It's perfectly simple, at least in concept. It's the engineering that's a bit tricky."
    "May be simple to you," Stirling muttered, "but it's perfectly impossible from where I sit. Look, perhaps I'll grant you that bit about consciousness being a shifting energy pattern. I've seen some pretty odd things, ran across a fellow once who swore on stacks of holy treatises he had yearly out-of-body experiences, and he wasn't a candidate for the loony bin, either. So maybe, for the sake of argument, I'll buy your story about projecting someone's consciousness some
where
else. But some
when
else? I'm not a credulous fool!"
    "Neither am I," Mylonas said very quietly. Stirling was struck again by the depth of fright in those dark eyes.
    "Suppose you explain it again. Pretend I'm a newspaper reporter or some chap on the dole, with no more science education than, say, that keg of ale can lay claim to. On second thought, perhaps you'd better leave off telling me
why
it works and just try explaining why it could prove dangerous in a terrorist's hands?" He had to fight the impulse to glance at Brenna McEgan.
    "They might well be interested," Mylonas said patiently, "because of the potential for
change,
which is inherent in the shifting of the fractural planes. Changing a variable, even a minor one, could have drastic consequences. I have tried to warn Dr. Beckett against rushing blindly ahead, before proper precautions can be taken, but he won't be stopped. Not by anything short of dying, anyway. Who do you think requested help from the Home Secretary? It was
not
Dr. Terrance Beckett. God help us, if terrorists ever get hold of this work."
    The level of tension at the crowded table rose abruptly, like a nasty miasma over a swamp, compounded of equal parts suspicion, fear, and anger. More than one set of eyes flicked uncertainly toward Brenna McEgan. She sat cool as a queen at her corner of the table, sapphire eyes focused on a speck of dust that floated somewhere over the center of the untidy tabletop. When nobody broke the awkward silence, Stirling cleared his throat.
    "Surely there's no way to actually change anything in the past? It's already happened, with no way to undo it. And even if you could, wouldn't paradox destroy any possibility of changing things, stop you before you got started?"
    Mylonas shook his head. "You're forgetting the infinite pasts part of the equation. If you projected the energy pattern of your consciousness into
a
past—say, the court of Henry II, as Dr. Beckett did, or even further back, to the time of King Arthur—"
    Cedric Banning snorted into his pint of bitters without quite laughing out loud. One of the graduate students dug her elbow into his ribs. As Mylonas reddened, Indrani Bhaskar put in mildly, "There is a great deal of evidence to suggest that King Arthur was quite genuine. Not a king, perhaps, but a real historical figure."
    Stirling grinned. "Yes, Dux Bellorum, and all that. Sixth century A.D., wasn't it? Last of the great Romanized