Many of those who have helped me over the past three years are named in the pages of this book and my first thanks must go to them. I hope to have done justice to them all. On a handful of occasions, in order to protect privacy, I have changed names. I have made this clear in the text where I have considered it important.

Professor Justin Byrne, Isabel Yanguas and Christopher Skala generously gave their time to read through early versions of the text. Their encouragement has been key to keeping the writer writing. I am indebted to Paddy Woodworth for looking through the Basque chapter and for his expertise on the GAL affair. David Fernández de Castro Azúa and Stephen Burgen similarly read through, and put me right on, Catalan affairs. Alan Goodman, Elizabeth Nash and Paul House also helped scrutinise the text. Responsibility for any errors that escaped, and for all the opinions expressed, remain exclusively mine.

In the Tiétar Valley I am indebted to Federico Martín and to many of those, especially Federico’s mother Clara, who shared painful memories of events from almost seventy years ago. In Barcelona my special thanks go to Silvia Català – not just for her help but also for two decades of friendship. Iñaki Gorostidi, Iñaki González, Nick Gardner, Iulen de Madariaga and Rosa Aliaga were invaluable in the Basque Country. The Elkarri peace movement has been a constant help there over the years. Prison officers at Spanish jails, who are targets for ETA, do not like their full names to appear in print. My thanks, therefore, go to Mercedes at Seville jail and Víctor in Granada. Alfonso de Miguel was a crucial flamenco contact as were many workers at the Esqueleto in Seville. Clea House and Monica Pérez diligently checked translations from Spain’s varied languages – though, once again, I have had the final word on these.

Amongst the institutions and public bodies to have helped me are the Biblioteca Nacional, the Audiencia Nacional, Patrimonio Nacional, the Museu d’Història de Catalunya, the Dirección General de Instituciones Penitenciarias, the Secretaria de Política Lingüística of the Generalitat de Catalunya, Omnium Cultural, the Fundación Nacional Francisco Franco, the Fundación Sabino Arana and the Mancomunidad de Municipios de la Costa del Sol Occidental.

Santiago Macías, Jusèp Boya, Montse Armengou, Justin Webster, José Antonio Sanahuja, Pedro del Olmo, Gijs van Hensbergen, David Sugarman, Ángel Palomino, Carlos Velasco, Mercedes Munarriz, Isambard Wilkinson, David Sharrock, William Chislett and several descendants of Salvador Ripoll have all provided help, often without knowing it.

Commissioning editors in London allowed me to chase stories that have provided much of the background, and some of the backbone, of the book. Ed Pilkington at the Guardian encouraged me to devote more than the usual time to looking at Civil War graves, while Harriet Sherwood generously gave me the three months off that I needed to finish writing. My thanks to them and the rest of the Guardian’s foreign and features desks. Elsewhere, thanks are owed to Bronwen Maddox, Gill Morgan and Tony Turnbull at The Times and to David Meilton.

My agent Georgina Capel has been an invaluable and enthusiastic guide. At Faber and Faber special thanks go to Walter Donohue and Nick Lowndes for their patience and understanding when dealing with a writer schooled in the rhythm of journalism. Thanks also go to Graeme Leonard for his seamless editing.

My most heartfelt gratitude, however, goes to my in-house editor, advisor, expert on flamenco matters and so much more, Katharine Blanca Scott. Two young Tremletts, Samuel and Lucas, have helped the author more than they can possibly know.