This book could not have been researched and written without the help of a good many people. The Watts branch of Agatha Christie’s family has been a rich source of new information, and I would especially like to thank Judith and Graham Gardner, daughter and son-in-law of Nan Watts, whose brother Jimmy was married to Agatha’s sister Madge; Miles Watts’s daughter Averil; Humphrey Watts’s daughters Dame Felicity Peake and Sizza Watts; Jane Davies whose mother Eleanor Campbell-Orde was Humphrey Watts’s daughter and a great friend of Agatha; Lyonel Watts’s granddaughter Fernanda Marlowe and her husband George Herford; and Adrian McConnel who was married to Humphrey Watts’s daughter Penelope.
I also want to express my gratitude to Anthony B. Martin, director of the Agatha Christie Centenary Celebrations; Christine Wilde; Marion and Ernest Chapel; Mr and Mrs David Tappin; Terrence Tappin; Patsy Robinson; Margery Campion; Richard D. Harris; Professor Donald Wiseman who helped Agatha and her second husband Max Mallowan excavate Nimrud; Mrs Loram for her recollections of Archie and Nancy Christie; Hubert Gregg who directed several of Agatha Christie’s plays; A.L. Rowse; George Gowler, Agatha’s butler at Greenway; and Millie Bush who was in service at Winterbrook House.
Others to whom I am indebted include Ian Blair, Chief Constable of the Surrey Constabulary and Geraldine Phillips; Barbara Hick of West Yorkshire Police; Ruth Harris of West Yorkshire Archive Service; Maggie Bird of the Metropolitan Police Archives Branch; Poole and Poole handwriting experts who deciphered a difficult sample of Agatha Christie’s handwriting; Susan Healy and Chris Bradley of Thames Valley Police (which now incorporates the Berkshire Constabulary); Dawn Smalley; Edith Butler; Edith Butler Nick Forbes of the Kew Public Records Office, holder of the Bradshaw Railway Guides; Ralph Barnet of the Surrey County Council who as an administrative ranger of Newlands Corner gave me a guided tour of the area and chalk pit into which Agatha’s car almost plunged; Eric Boshier and Wilfrid Morton who as members of the Surrey police took part in the search for Agatha. Richard Brotherton and Anders Ditlev Clausager of the British Motor Industry Heritage Trust; Mark Priddey of the Oxfordshire Archives; Detective Sergeant Christopher Roberts, formerly of the Camberley Police Force; William Taylor of the Royal Observatory, Edinburgh, and Ian McGregor of the British National Meteorology Library and Archive for supplying moon and weather conditions for 3 December 1926; Bruce Hoag; Lisa Spurrier, Robert Hale, Elizabeth Hughes and Mark Stevens of the Berkshire Record Office; Patricia Willis of the Surrey Record Office; Eamon Dyas; R.M. Jones; Celeste Kenney; Althea Bridges; Colin Price; Bill Indge; Tibby Kull; and Jack Boxall who with his father searched for Agatha. Others include Dame Jean Conan-Doyle for information about the Christies’ mutual friend Air Commodore Rankin; Gina Dobbs of Random House for permission to examine Agatha’s business correspondence with the Bodley Head; Michael Bott of Reading University; Michael Rhodes, former keeper of Agatha’s correspondence for the Bodley Head; Stuart Ó Seanóir of Trinity College Library, holder of Judge Bodkin’s correspondence; Glenise Matheson of the John Rylands University Library; Christopher Sheppard of the Brotherton Collection, Leeds University Library; Catherine Cookson of Marylebone Library; Brigadier K.A. Timbers, Historical Secretary of the Royal Artillery Institution; Richard Bland of Clifton College; Roland Lewis; Stewart Gillies and the staff of the British Library; Helen Pugh of the British Red Cross; and Ray Martin and the staff of the British Telecom Archives.
My thanks, too, go to Kay Farnell of the Automobile Association; Margaret de Motte for access to the papers of the Watts Family of Abney Hall; Peter Berry; Lord Brabourne and the Trustees of the Mountbatten Archive; Gwen Robyns; Kai Jorg Hintz; Jean Debny; Tim Raven; Christopher Dean; Barbara Reynolds; Phillip L. Scowcroft; Jacob Ecclestone; Jacqui Kanaugh of the BBC Written Archives; Mike Dolton of BBC Sound Archives; His Grace the late Duke of Northumberland; Michael Baxter; Charles Ward; and Philip Garnons-Williams, owner of a 1920s Morris Cowley car, who acted as my driver when I restaged the journey Agatha took on the night of her disappearance.
I have also been helped by Shari Andrews of the Old Swan Hotel, formerly the Harrogate Hydro; Malcolm Nessam; Mr Stay of Harrogate Library; the staff of the Library of Congress; Mr T. Lidgate; St Catherine’s House and Somerset House; Michael Meredith; the staff of Bristol Library University; the staff of Kensington and Chelsea Libraries; Sally Harrower of the National Library of Scotland; Linda S. Moore of Charles Parkhurst Rare Books; the late Kathleen Tynan, who scripted the film Agatha and to whom I spoke before her death, and Leon Wieseltier, executor of her estate; Roxanna and Matthew Tynan, who since then have helped to make it possible to view their mother’s private research papers and other related matters; and Mr and Mrs Wood for showing me around their home at Styles, Sunningdale.
Finally, special thanks is due to a small band of dedicated and knowledgeable Christie enthusiasts who kept me informed and whose modesty prevents them from being named here.