Adolescent friendships are unique: The close friends we make as children almost become part of our family, watched over equally by supervising parents, teased or ignored by resident siblings. Glad to be included, they become part of the whole and accept conditions without thought or judgement. On the other hand, our adult friends find us as self-sufficient beings, with loosened family ties. Only the friends of our adolescent years perceive the context of our family’s past and the adults we will become. More observant than young children, they witness the stresses in these families they know and, being teenagers, they sometimes judge, although they rarely blab about what they learn. Self-conscious and plagued by hormones, most teenagers prefer to keep secrets. These are the undercurrent themes of Bittersweet, Miranda Beverly-Whittemore’s new novel about identity and lies. Mabel Dagmar is her narrator, a working-class girl dependent on scholarships for her college education and the opposite of her roommate Genevra Winslow, the assured descendent of a wealthy, Eastern family. To Mabel, the Winslows exist in rarefied existence of Ivy League schools, named summer cottages and the kind of confidence that only comes from generations of independent wealth and she joins Ginevra for…