Jean is the reliable, dependable one--at home or at school. ""But being dependable,"" says Grandma, ""isn't the same as being walked on."" Thus the title--and a sturdier story than last year's heart-tugging Just Like a Real Family. Jean fumes when older sister Belinda, 15 to her 12, doesn't turn up to fix dinner or to stay with little brother Mark; she's furious at best-friend Stacy for borrowing her science book, the night before a test, and not returning it as promised. Yet she herself realizes that she doesn't have to stay after school and help decorate for Parents' Day--she could say she has a job: cleaning fish bowls and fish tanks to earn money for the animal-shelter puppy, Marshmallow. (""What does it matter if John and Stuart stay but I don't? Why does it matter so much what Miss Brookner thinks of me?"") Holl handles the situation dextrously, advancing Jean little by little--through Belinda's failure to repay Marshmallow money, through the stresses of fish-tank-cleaning--to the moment when Grandma, again, put her finger on the problem: Jean must enjoy ""being the 'girl everyone can count on.'"" ""I want you to believe that others like you for yourself, not for the things you are willing to do for them."" Not that being dependable doesn't have its place: Jean gets Marshmallow short of the stipulated $15, for volunteering help at the shelter. And her new independence, she knows, doesn't extend to Marshmallow either. It's tidy, for sure--but a useful lesson soundly and agreeably presented.