I am most grateful to Avi Lifschitz and Brian Young, as well as to two anonymous readers for OUP, for reading the complete draft and making many acute suggestions; likewise to Maxine Berg, Dmitri Levitin and Sarah Mortimer for constructive criticism of individual chapters, which resulted in their considerable improvement. I also owe a great deal to Silvia Sebastiani and her colleagues at the École des Hautes Études en Sciences Sociales, Paris, and to my colleagues and students on the MPhil in Political Thought and Intellectual History at Cambridge, where many of the ideas in this book were tested in discussion. Fo Orbell gave invaluable assistance in identifying the images used as illustrations. Finally, and as ever, I am grateful for the support of my family, to the newest member of which this book is dedicated.