As a child, my mother lived in Paris in one of the apartments of 54 Avenue d’Iéna, a handsome house close to the Arc de Triomphe, and Aline de Gunzburg lived in another. First as girls, then as adults, the two were the closest of friends. By the time I came up to Oxford in 1956, my mother had died, Aline had married Isaiah Berlin, and the two of them were as good as family to me. I was always welcome at their house in Headington, a typical English gentleman’s residence built in stone in a setting of lawns and old trees. A manservant, usually Portuguese, opened the front door. The ground-floor rooms were spacious, and Aline’s classical good taste and beautiful possessions made the most of them. To the right of the hall was a study for Isaiah, a room of organized untidiness in which he sat for hours dictating letters that kept selected friends up to date with his news and views, his anxieties and hopes, and since his death they have been edited and published in four hefty volumes. He was generally supposed to be working on a book, even a series of books, about the political and philosophical ideas that have made the world what it is. Exhausting his time and his energy, that huge and self-perpetuating correspondence excused the missing masterpiece.

Isaiah wore heavy, old-fashioned suits, and out of doors an old hat of brown felt, giving him a conventional appearance.