H. Beam Piper: Temple Trouble: Miracles to order was a fine way for the paratimers to get mining concessions—but Nature can sometimes pull counter-miracles. And so can men, for that matter...

I'll bet you did not know that our little earth is not limited to the single time line on which we happen to muddle along. That's right; There are actually thousands, indeed, many millions of parallel time lines, each existing alongside all the rest, using the same real estate (our earth), but following their own path. Some extremely primitive, some very advanced, but all blissfully unaware of the others. Of course this does not affect you or me at all, unless ... unless one of these time lines discovers the existence of the others and then a way to move easily back and forth from one to the other. Then a few problems might happen. Well, it has happened and the ParaPolice are kept busy sorting out things like what happened here on an earth time line where Yat-Zur, the 6 armed god, battles Muz-Azin, the Crocodile god ... or something like that. Piper again delivers a well written, imaginative tale for our enjoyment.