The idea for this book was originally suggested to me by my then editor at Allen Lane, Georgina Laycock, who also helped me steer it through its initial (and rather turbulent) development stages. Her successor, Thomas Penn, has been a great source of advice and encouragement subsequently. The first two chapters have benefited hugely from discussions with Professor Nicky Milner (York University) and the sections on Stonehenge owe much to Professor Mike Parker Pearson, of University College London. Other prehistorians who have been very free with their advice include Chris Evans, Clive Waddington, Martin Bell and Maisie Taylor. On the production side at Penguin, I have worked with a great team including Richard Duguid and Lisa Simmonds, illustrator Jeff Edwards, copy editor Monica Schmoller and indexer Marian Aird; Casiana Ionita ensured that the production process ran smoothly. As ever I owe a huge debt of gratitude to my agent Bill Hamilton, at A. M. Heath and Co. It has been far too long, but maybe now Maisie and I can have a holiday together.