A funny children's story dealing with wife abuse doesn't sound promising, but Byars pulls if off with her understanding light touch. She assigns the problem a manageable distance by making the abused wife not Jackson's mother, who's divorced, but his beloved former sitter Alma, a simple soul devoted to Jackson, her own baby Nicole (named for a soap-opera character), her extensive collection of Barbie dolls, and shopping. Jackson's growing concern over Alma's bruises and black eye is all the more poignant for his mother's dismissal of his fears, and for Alma's avoidance of Jackson for fear that her husband will carry out his threat to attack the boy as well. The humor, which never belittles Alma's troubles, is sometimes slipped in as anecdotes about Jackson's pal Goat or his incorrigible cutup father. Sometimes the funny scenes are more central, as when an anxious Jackson and an excited Goat, 11-year-olds sitting on pillows for height, manage to drive Jackson's mother's car to take Alma to a battered-wives' shelter in a nearby town. That time, Alma changes her mind en route; but later, when she and the baby are both hurt badly, Jackson's mother steps in and gets her to the shelter. A plot outline of Cracker Jackson might suggest a banal gloss on a trendy problem; but Byars gives Jackson's part in the drama an affecting cast of feeling--never deep or disturbing, but never goopy either, and always within an 11-year-old boy's emotional framework.