Everything you need to understand or teach I'm Not Who You Think I Am by Peg Kehret.
I'm Not Who You Think I Am, published in 1999, is a suspense novel in which Ginger Shaw, a thirteen-year-old, is stalked by a strange woman who claims to be her biological mother. Ginger, whose parents have always entertained her with stories of her birth, had never before considered the possibility of being adopted. However, the woman's persistence causes Ginger to doubt her own identity and, finally, to fear for her life. The novel's parallel story concerns the town's most prominent citizen's vendetta against the girls' basketball coach, a much beloved teacher and Ginger's mentor. Suspense is interwoven with issues of loyalty and honor. The two stories converge at a climactic school board hearing, as Ginger discovers through this compelling and suspense-filled novel some important truths about who she is and what values she holds dear.