With its unique, oversized format (15 7/8 x 19 3/8), My Big Dictionary is touted as the first large-format dictionary available for the preschool and kindergarten set. While the concept sounds appealing and the aims are high (a list of ten activities for parents and teachers to do with children appears on the inside front cover), one wonders whether there is more hype than substance here. For one thing, the oversized format is actually unwieldy and hard to handle; young children will need help with it -- which may he frustrating to a child who wants to ""do it myself!"" Also, the entries are rather arbitrary. The letter A has six words, while the letter B has 18. Under B there are listings for ""ballerina,"" which shows a girl dancing, and ""ballet dancer,"" which shows a boy. Need two entries so close in meaning have been included? To deal with the gender issue, it might have been better to have had the words ""ballet dancers"" and shown both boys and girls in ballet positions. There are also large drawings filled with a variety of things beginning with the letter they are meant to illustrate. Thus, the page for the letter C shows an elaborate, detailed drawing of a circus, depicting a cheetah, cows, camels, cars, clowns, Christmas trees, carriages and crows (to name just a few). While these drawings are delightful and inventive in and of themselves, one wonders about their value here. A very young child is apt to be confused by the intense, busy images and lose sight of the lesson, which is that all the words begin with a certain letter. Older children, for whom this seems more appropriate, may already have moved on to a different format, such as the American Heritage Picture Dictionary, a newly revised edition of a 1986 volume that has 900 entries and 650 illustrations. All in all, My Big Dictionary is a useful volume -- but only with adult supervision.