The biographer revels in the considerable personal shortcomings of the admittedly gifted writer. "She was a horrible human being," recalls Otto Penzler, one of her publishers. It's an apt eulogy for a novelist whom Graham Greene, rather more charitably, dubbed "the poet of apprehension," a 20th century demiurge whose "world we enter each time with a sense of personal danger, with the head half turned over the shoulder." The first words of Joan Schenkar's splendid, sinewy new biography, "The Talented Miss Highsmith: The Secret Life and Serious Art of Patricia Highsmith," concede the point: "She wasn't nice," Schenkar admits; "She was rarely polite." Yet the "toxic brilliance of [her] trail goes on glowing" 15 years after her death in 1995 -- when "she drove a last, devoted visitor from her hospital room and then died unobserved."