I AM HUGELY grateful to everyone who spoke with me when I was working on this book: Finn Beales, Dr. Philip Cleland, Jeff Davies, Toby Eckley, Ieuan and Gwyneth Evans, Chris Havard, Robert and Llinos Jones, Alun Price, Matthew Price, Rose and Elwyn Price, Walter Price, John Pugh, Ernie Roberts and Robert Tyler.

And to everyone who read and commented on its various drafts: Charlotte Ward, Philip Gross, Clare Alexander, Will and Jenny Bullough, Richard Gwyn and Gerard Woodward. And, of course, Max Porter and Daphne Tagg at Granta, and Noah Eaker and Kathy Lord at Random House.

I would also like to thank (the great) Julian Broad, everyone at the Brecon and Radnor Express, Trefor Griffiths for the permission to quote W. H. Howse, and Christopher Meredith, whose poem “Borderland” (in the excellent Air Histories) was on my mind throughout.

For her work on the tree photographs, and for most other things, my thanks and love to Charlotte, as ever.