Proof

On the eve of her twenty-fifth birthday, Catherine, a troubled young woman has sacrificed years caring for her brilliant but unstable father, a famous mathematician.  As if her life has not been difficult enough, Catherine must now deal with her own volatile emotions concerning the arrival of her estranged sister, Claire; a burgeoning romance with Hal, a former student of her father’s, and the discovery of a mysterious notebook that draws Catherine into the most difficult problem of all: How much of her father’s madness—or genius—did she inherit?