I am very grateful to the experts who have contributed chapters to this report, and whose conversation at the CER board meeting in summer 2011 inspired this publication in the first place. They have been most patient and gracious during the editing process. The conversion of five different contributions into one report required considerable simplification and explanation as well as the addition of many footnotes. I take full responsibility for any errors that have crept in during editing.
I also wish to thank my many CER colleagues for editing and proofreading the report, in particular Hugo Brady. David Buchan provided invaluable advice on early versions of the chapters. As ever, a special thanks to Kate Mullineux for layout and production.