In her reworking of the classic lullaby, Long intentionally de-emphasizes the materialism of the original, making no promises of such grand gifts as a diamond ring or horse and cart. Rather, this Mama character--one of Long's (illustrator of Ten Little Rabbits) familiar, gentle bunnies--comforts her cotton-tailed child with vows to share the sound of cricket calls and a song on her banjo, the sight of a shooting star and the harvest moon and, finally, ""As that moon drifts through the sky,/ Mama's going to sing you a lullaby."" Blending images of nature with such timelessly reassuring items as teddy bear and picture book, Long's song is gracious if not especially inventive. The art, meanwhile, is both soothing and diverting. While the audience (like Mama's cooperative offspring) may well find their eyelids growing heavy, they will be happily distracted by the pictures' fetching particulars: a patchwork quilt displaying miniature renditions of objects mentioned in the lullaby and, on the bedside table, a book illustration that hints that this sleepy rabbit is reading the same book that they are. Ages up to 5. (Mar.) FYI: Notecards (set of 16, $9.95, ISBN 0-8118-1643-5) and a 10""-tall plush doll ($14.95, -1792-X) based on the book are being released simultaneously.