For eight years I rented a small house in Oxford overlooking the canal. The landlord, a poet and novelist younger than myself, had moved with his family to New Mexico. At his desk I managed to write three books, beneath shelves containing editions of his work. I can’t explain why it took me so long to reach up and open those books, but when I finally did, it was extraordinary to discover how similar were our trajectories: same prep school and university; two young sons; novels set in North Africa and Peru; a gap year working on an Argentine estancia.

Until...