Ann Wroe has become a daredevil writer. The obituaries editor of The Economist, she is by education a historian; she followed her first book, a journalistic inquest into the Iran-Contra Affair, with a study of life in a medieval French village. Such conventional approaches began to fall away in her third work, the biography of ‘an invented man’, as she called him: Pontius Pilate, of whose life almost nothing is known. She later wrote what might be described as a meta-biography of Shelley, in which she sought to discover from the inside what it might feel like to be a spirit fallen into a cosmos it is not meant for, burning to find its way back to some better star. She patterned this excursion on the four elements. Another book, a biography of Orpheus, took as its grid the seven strings of a lyre. Incarnating this figure of myth through the landscapes and legends of his native Thrace and works by authors from Ovid to Rilke, Wroe rendered her new ‘invented man’ in tones of darkness as well as light, attributes Orpheus inherited from his father, Apollo. This is where she began to descry the contours of her latest book, a biography of light itself.