Time's Eye by Clarke and Baxter

OK, but not really AH. The alien space bats slice and dice earth's history so Alexander the Great gets to fight a battle with Temuchin (Genghiz Khan) as they march across alternating swatches of ice age and other bits of weather, ecology, and culture from all eras of history.
I've heard about this...any good? I enjoyed their last collaboration together (The Light of Other Days).