From newcomer Sinclair, the coming-of-age story of a black girl in 1960's Chicago. Jean ``Stevie'' Stevenson is a child of the working poor. Her father is a hospital janitor, her mother is a bank teller, and Grandma owns a popular South Side chicken-stand. Sixth-grader Stevie, meanwhile, is tired of her mother's rules, her refusal to countenance ``black English,'' her attempts to make Stevie a dreaded ``L7'' (square). Stevie's dream is to be popular and cool, and her wish is granted when ``all the way cool'' Carla invites her to a party. Soon Stevie has had her first period, her first kiss (from sexy Yusef), and is learning that cool is not necessarily kind, for that dog Yusef has his classmates spy while the two show themselves to each other. All this is fresh and authentic. The trouble starts with Stevie's arrival at high school, which coincides with the ``black is beautiful'' period (it's 1967). Here, the flow is disrupted by obvious setups intended to make points about race and sexual orientation. Stevie and Carla happen on their white art-teacher having a date with a black man--puppets miming the interracial experimentation of the period. At school, the sympathetic Nurse Horn puts Stevie in a quandary: Is it possible to be friends with a white woman, who may even be ``funny'' (lesbian)? The question overshadows Stevie's almost consummated relationship with Sean, a straight-arrow senior, and although the good nurse answers it in best Ann Landers style (``because you have a schoolgirl crush on me doesn't make you a homosexual''), Stevie ends up dwarfed by her author's agenda. Sinclair's story works fine when she gives her characters room to breathe. A fair-to-middling debut.