Third and fourth in the Sisters Series, a quartet of novels about the year-apart girls in the Gray family. Phoebe and Daphne are in the sixth and seventh grades; these two fill out the junior-high years. Cassie, the pretty, popular sister whose life revolves around appearances and friends' opinions, seemed the least sympathetic sister in the earlier books. Here, she tries out a typical fantasy: rich, sophisticated Dana chooses her as friend. At first Cassie's head is turned; she slights her best friend and even forgets to keep a long-sought date with a boy. When it turns out that Dana is a deprived child in her own way--her busy parents leave her in the inadequate care of servants, and Dana has reciprocated by becoming a kleptomaniac--it's to Cassie's credit that she decides to help Dana make a real place for herself in spite of the fact that Dana has played her an ugly trick. Lydia, eldest and the family activist, leads a split from the student newspaper and starts the Alternative, a journal that begins with easy success in a campaign to improve school lunches and goes on to a rockier confrontation when it advocates having girls on the football team. Feisty Lydia is so busy defending her cause that co-captain Sam needs considerable persistence before she lets him explain that he's on her side. Though written in simple terms and without much elaboration, these approachable stories of contemporary life deal sensibly with real issues and concerns. Kaye has succeeded in presenting four remarkably different personalities, yet plausibly made them members of a single, busy, affectionate, realistically competitive family. Each book is self-sufficient; yet, read together, they reinforce one another. They should make popular, worthwhile reading for their intended audience.