DANCING IN THE DARK by Janet Hobhouse (Anchor: $9; 229). Hobhouse’s <<>> most/÷ousø portrait of an early ‘80s yup-scale New York marriage s eems more dated than many novels from the ‘20s. Morgan and Gabriella Callagher lead a life of hip surfeit: Despite good jobs, a big apartment and a plethora of luxury goods, they’re thoroughly bored with themselves and each other. Gabriella gets vicarious thrills by going to trendy discos with her seemingly untrammeled gay friend, Claudio, and his “band.” An earthquake in Mexico City reminds her of her mortality and commitment to Morgan in an abrupt epiphany that brings the novel to a more or less happy conclusion. The economic downturn and the AIDS crisis have so thoroughly ravaged the Callaghers’ milieu that their otiose whims seem impossibly remote. Hobhouse’s characters stand as mute witnesses to the changes and sorrows America has experienced during the last decade.