I would like to express my gratitude to the publishers, and in particular Tomasz Hoskins, for commissioning this and the two previous books in this trilogy. Working with I.B.Tauris has been a happy collaboration. I am also thankful for the many people with whom I have discussed ideas drawn on in this work. I would also like to thank Sun Jiabao and Jolita Pons for reading through the first drafts and making many helpful and useful comments. Finally, I would like to thank Sarah Terry for her hard work on the copy-editing.