James Joyce’s troubled but brilliant daughter, Lucia, has always been seen as something of a peripheral figure in her father’s life, and Joyce scholars have traditionally assigned more literary importance to Joyce’s wife. But a new biography of Lucia suggests that she, not her mother, was Joyce’s primary muse. The book is important not only because of its controversial thesis, but because it exists at all. In recent years, Joyce’s grandson, who oversees the author’s literary estate, has become increasingly aggressive in protecting his grandfather’s legacy, to the point of forbidding scholars from quoting from Joyce’s letters.