'Who made this mess?' 'The gorilla did it'"" Hazen banks on the familiarity of the above exchange to numberless preschoolers and their mothers, then goes on to make both parties happy by having the ""gorilla"" clean up the mess he made (with the child's help) and receive a cookie as a reward. ""He says he's sorry. . . and he really means to be a good gorilla."" That's all there is to it, which isn't much considering that the imaginary scapegoat is no newcomer on the picture book scene, but Ray Cruz (who seems to specialize in these controlled daydreams) manages, with a fine line blue gorilla on black and white pages, to project both the animal's dreamlike presence and its hairy superreality.