Bad historical novelists assume that people always live at the spearhead of their age. Good ones, like Francesca Kay in her fourth book, know that even when the world spins ‘faster than a weathervane in a gale’, most hearts and minds will tarry in the past, behind events. The Book of Days unfolds in a village north of Oxford in 1546 and 1547, as the unnamed old king dies and the accession of his child heir brings another round of ‘newfanglery’ in faith.