As she did with each of her previous three novels, including the best-selling The Dogs of Babel, the D.C.-based writer Carolyn Parkhurst again performs complex feats of storytelling with a deceptive ease and grace. In Harmony (Pamela Dorman, $26), Parkhurst uses the alternating voices of a mother and her eleven-year-old daughter to narrate the story of a family buckling from the strain of raising a child on the autism spectrum. Thirteen-year-old Tilly is brilliant but socially challenged. Her language is unrestrained and sometimes vulgar, and her behavior veers between terrifying and odd: during a family dinner at a Chinese restaurant, for example, Tilly launches into a sophisticated critique of regional cuisines while succumbing to a series of physical tics that have her twisting and gyrating and touching her head to the floor. After she is expelled from school, the family takes radical action. Under the sway of a charismatic child behaviorist named Scott Bean, they give up their comfortable lives in the District to move to rural New Hampshire, where Bean is establishing a community for families wrestling with similar issues. Parkhurst’s haunting prologue foreshadows the fact that this bucolic setting will not offer a panacea. There may be no easy answers, but there is love and family to fall back on, as well as palliatives like this book.