What is Dust? Philip Pullman has been promising an answer to this question since the publication of the last volume of His Dark Materials, the trilogy of novels that took as one of its starting points Blake’s contention that in Paradise Lost the poet Milton was unknowingly of the devil’s party. We were told that Dust was released when a child emerged into adolescence and their daemon settled into one shape; the Magisterium, an autocratic church, feared it and determined to control it; carelessness with it created ecological havoc. After seventeen years La Belle Sauvage, the first volume of The Book of Dust, doesn’t quite answer the question but then, it is set some ten years before the beginning of His Dark Materials. Lyra Belacqua is an unwanted baby around whose head prophecies are brewing; already the philosophers and explorers of her weirdly familiar but off-kilter world are on the case of Dust, recognising that it has something to do with consciousness and that ‘consciousness can no longer be regarded exclusively as a function of the human brain’. In launching the book, Pullman has referred to ‘dark matter’ and the fact that the scientists still don’t know what it is.