The idea for this book came from the Political Studies Association (PSA), which wanted political science to play its part in the 800th-anniversary celebrations of Magna Carta. Professor Justin Fisher of the Magna Carta Institute at Brunel and Jennifer Hudson of the PSA Executive asked me to organise a conference and a book, and I willingly agreed. It could have been a challenge to find something new to say about Magna Carta, but thanks to the contributors to this volume, I am confident that we have succeeded. So my first thanks go to them, for finding the time to write very interesting chapters and for coming to the United Kingdom to discuss their contributions with each other at a workshop held at the Constitution Unit in the School of Public Policy at UCL in June 2014.

Thanks must also go to the others who attended the workshop – Conor Gearty, Clodagh Harris, George Jones and Colin Munro – for their comments on the draft chapters; and thanks to our administrator, Ben Webb, for organising it with his usual enthusiasm and efficiency. We also express special thanks to the interns who have supported this project: Annabelle Huet, Daniel Helen and Chrysi Kalfa. Daniel's expertise as a medieval historian was particularly valuable.

For including the book in the Cambridge University Press series on comparative constitutional law and policy, we thank the editors, Zachary Elkins, Tom Ginsburg and Ran Hirschl. Our thanks also go to the anonymous reviewers of our book proposal and to John Berger, our editor at Cambridge. And we thank the PSA for funding the project and paying for the workshop in 2014 and the conference to launch the book in 2015. Without the PSA's foresight and support, this book would not have happened.

I reserve my last but warmest thanks to my colleague and co-editor James Melton. He has done all the hard work and ensured that everyone delivered on time (a first in my experience of edited books); he did so throughout with tact, good humour and quiet efficiency.