This title offers an overview of concepts related to time, listed in alphabetical order: “A is for Almanac,” “D is for Daylight Saving,” “E is for Einstein,” “G is for Greenwich Mean Time,” and “K is for Kukulcan Pyramid.” Accompanied by sweet, painterly illustrations that hark back to earlier eras, the entries begin with four-line rhymes and go on to clear, well-researched prose explanations, rendered in a fairly small typeface. These are simple and brief introductions to a mix of basic ideas (such as explanations of a week, a shadow, and the night sky) and much more challenging concepts (definitions of Zulu time and verge escapement). Other books in this series are geared to readers ages six to 10, but this title defies categorization: some content is straightforward, but much of it is too sophisticated for primary students. VERDICT An additional purchase where interest in time concepts is high.