Looking at other people's libraries is one of life's simple pleasures. Over the holiday weekend our family visited Sissinghurst Castle, home in the 1930s of diplomat and politician Harold Nicolson and writer Vita Sackville-West. The glory of the place is its garden, but I loved the library, which had the authentic smell of old paper and bookbindings.

Some 30 years or so ago I dipped a bit into Nicolson's Diaries. He was, like Keynes, a critic of the Versailles Treaty. Later he had a career as an MP and (in the 40s) a BBC Governor. I've just ordered the diaries to remind myself – the political diary genre, ranging from Richard Crossman through Alan Clark to Chris Mullin is extremely varied of course, but for the most part an interesting read if only for the insight into the distinctive way of thinking a life in politics imposes on people.

The most envy-inducing library I ever visited, though, was that belonging to Mario Vargas Llosa in Madrid. I went to interview him for a BBC Radio 4 Analysis on globalisation. (I can't link to it at the moment as the volume of Royal Wedding traffic on the BBC website is preventing it from responding to any other requests!) It was an old building near the palace. The room had a mezzanine, with his desk on the gallery and sofas around a low table on the lower level. And books. Lots of. It was hard to concentrate on the interview.