A fantastic essayist, the inimitable Muriel Spark addresses here the writing life, cats, favorite writers (the Brontës, T. S. Eliot, Robert Burns, Mary Shelley), love, Piero della Francesca, life in wartime London and in glamorous “Hollywoodon-the-Tiber” 1960s Rome, faith, and parties (on her first New Year’s Eve, as a baby sipping her mother’s sherry: “I always loved a party”). No one was as “fearless and original” (TLS) as Muriel Spark, who believed that “art is an act of daring.…