Dame Muriel Spark, whose spare and humorous novels made her one of the most admired British writers of the postwar years, has died in Tuscany, Italian officials said Saturday. She was 88. Spark died Thursday in a hospital in Florence, said Massimiliano Dindalini, the mayor of the Tuscan village of Civitella della Chiana, where Spark had lived for almost three decades. Spark wrote more than 20 novels, including "The Prime of Miss Jean Brodie." She had lived in Italy since the late 1960s, first in Rome and later in a converted 13th-century church in Tuscany with her friend of many years, painter and sculptor Penelope Jardine.