Siblings Jack and Annie travel on yet another Merlin Mission, this time back twelve hundred years to Baghdad's golden age so that they can deliver a book of Aristotle's writings to the caliph. Osborne often enlists stock writing (""her shocked gaze""; ""'But--how--what?' stammered Jack"") that's unworthy of her detail-rich story, which is enhanced by Murdocca's dramatic black-and-white art. (c) Copyright 2010. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted. All rights reserved.