A time traveler goes back in time and provides technology to an Islamic conqueror that allows him to win a war over Christendom in Europe, setting up an alternate reality where Islam is observed and practiced. I've read several of Khoury's previous books and remember them as being interesting, but it was hard not being bored out of mind reading the preview of this one. Plus time travel. Is it bad that because it's so easy to screw up time travel that it drives me crazy when authors put it in their books?