I borrowed many ideas from other clever people, and there are too many books I read and people I quizzed to thank them all, but here are a few of them.
I am indebted to my agents Sophie Lambert and Kevin Conroy Scott for their boundless enthusiasm, advice and encouragement in making this happen. Of the many who read the bad drafts – Victoria Vazquez and Barbara Prainsack read every page and deserve medals. Robyn Fitzgerald, Andrea Burri, Lynn Cherkas and Raj Gill also contributed including help with preparing twin interviews. Lesley Bookbinder, Susan Hochberg and Sophie Spector also helped, as did Emma Walker of the BBC. I had many conversations with helpful colleagues including Jordana Bell, Jonathan Mill, Robert Plomin, Nick Martin, Stephan Beck, Mitch Blair, Roz Kadir, Philip Sambrook, Keith Godfrey, Niloufar Safnia, Bryce from Chatter creek, the guests of the ‘Fleur de Lampaul’, Jeff Craig, Andy Feinberg and Manel Esteller. I am grateful to KCL and the St Thomas’ Charitable trustees for allowing my mini-sabbatical to the CRG Barcelona where Xavier Estivill was a great host, assisted by the inspirational theories of ‘the X-Men and Chicas’, Elisa doCampo, Monica Coronel and Susana Guzman and the rest of the team. Thanks to Debbie Hart and Victoria who looked after the department in my absence and to my family for allowing my epi-vacation. I’m grateful to the European Research Council for my epigenetics award and the Wellcome Trust and EU for long-term funding. My colleague Wangjun and team at BGI in China have been great collaborators on the EpiTwin project. I would like to thank my editor at Weidenfeld & Nicolson, Bea Hemming, who has been a fantastic support in shaping and improving the drafts.
I have tried to reference as many articles and sources as possible, but many will have been omitted. For this and any factual errors I take the blame. Finally, I’d like to thank all the amazing twin volunteers who willingly and unrewarded give up their stories, time, bits of their bodies and DNA for the advancement of science.