A few months ago I went to dinner with an old friend, a retired professor of great distinction who suffered throughout his career from the vituperation of his academic colleagues who took a view of their chosen subject almost diametrically opposed to his own. Now that he has been proved right, and they have been proved wrong, they denigrate his work as having been nothing more than a statement of the obvious. It isn’t only totalitarian dictators, it seems, who rewrite history.

My friend was reading when I arrived, but made guilty haste to put away the book as I entered the room. He could scarcely have been more embarrassed had he been caught perusing an album of pornographic postcards. Under the promise of total secrecy, he confessed that he had been reading the short stories of W. Somerset Maugham. In fact, I had already guessed as much: an habitué of secondhand bookshops, I can now judge a book by its cover...