It had once amused my father to hand over a book with colored plates (an account of a journey through Persia) for me and my eldest sister to destroy. Not easy to justify from the educational point of view! I had been five years old at the time, and the picture of the two of us blissfully pulling the book to pieces (leaf by leaf, like an artichoke, I found myself saying) was almost the only plastic memory that I retained from that period of my life.