Seeing no reason why the dead shouldn’t be acknowledged along with the living, my thanks are due first to Professor John Maynard-Smith, who ignited my lifelong passion for the biological sciences and planted some of the questions which provoked this novel. I am deeply grateful for the underpinning encouragement of my agent Rupert Heath, the sensitive editing of Ros Porter and Tamsin Shelton, and the enthusiastic support of everyone at Oneworld. Thanks are due to David Hill for the ovation and to Catherine Smith for front-line support. But the deepest gratitude is due to my husband Paul, who has made all this possible, and who loved this book from the start.