Gr 4-7 Yet another solve-it-yourself mystery book. Although the short puzzles (one to two pages) are full of logic and quite clever in their solutions, they lack the charm of the ``Encyclopedia Brown'' stories (Morrow) by Sobol. The format will give these stories appeal to middle and upper elementary children, but the puzzles are very abstract and many will prove too difficult for them to solve. A book that may attract above-average thinkers. Kristie Gallion, Billings R-IV Sch . Lib . , Miss.