It's About Time there was another, since Miriam Schlein's book by that name is primarily about concepts of relative time, less about how to tell it precisely, and What Time Is It, Jeanne Marie? clocks the hours but doesn't explain how. This is rather mechanical, but it works. Essentially it is a demonstration, via simple drawings of a clockface, of how the hour and minute hands move and mesh. The old device of making a paper plate clock is introduced also, and a simple explanation of how the wheels turn inside winds up. Cheerful sketches stave off tedium throughout.