When X is for eXplain there's a problem, especially in an alphabet book that purports to stress the importance of accuracy and reliability in science. The book's subject is so broad that the poems, already awkwardly rhymed, are stretched extra thin to accommodate content. The accompanying illustrations, though stiff, are painterly. (c) Copyright 2011. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

This latest entry in the publisher's alphabet series packs a lot of elements into just 26 entries. The science ranges from aviation to zoology, but the featured words are general terms that are useful for all scientists adapt, build, and compare, for starters. Each page includes a four-line poem featuring that page's concept; a sidebar of fairly sophisticated text that describes the discovery of a particular scientist; and gentle yet realistic illustrations. For the poems, which don't always scan, the author sometimes takes an informal tone in describing the scientists, many of whom won't be familiar to elementary-school students: In his classic experiment, / Ivan put dogs in the mood / of licking their chops and slobbering / even without having their food. But the intelligent text makes up for the uneven poetry, elucidating an impressive variety of fields, continents, and time periods (from 265 BCE to the 1991 introduction of the World Wide Web). Ideal for young scientists who haven't yet settled on their specialties.--Nolan, Abby Copyright 2010 Booklist