My first debt is to the colleagues with whom I have researched and studied over the years. But I’m equally grateful for the penetrating cosmological discussions I’ve had with non-specialists: these always bring a fresh perspective, by highlighting the ‘big picture’, and reminding me that the most important questions are still unanswered. Special thanks, therefore, to David Hart, Graeme Mitchison, Hans Rausing, and Nick Webb. The present book is intended for general readers of this kind. I’ve tried, while avoiding technicalities, to set new discoveries in context, to distinguish well-based claims from speculations, and to emphasize the mysteries that lie beyond.
I thank John Brockman for inviting me to contribute to the Science Masters series, and for his forbearance during the book’s slow gestation. Toby Mundy and Emma Baxter of Weidenfeld and Nicolson were very supportive throughout the editing and production process. I’m grateful to them; also to Richard Sword and Joop Schaye for preparing the illustrations, to Brian Amos for the index, and to Judith Moss for secretarial help.