“When you're writing a book, it's rather like going on a very long walk, across valleys and mountains and things, and you get the first view of what you see and you write it down. Then you walk a bit further, maybe up onto the top of a hill, and you see something else. Then you write that and you go on like that, day after day, getting different views of the same landscape really. The highest mountain on the walk is obviously the end of the book, because it's got to be the best view of all, when everything comes together and you can look back and see that everything you've done all ties up. But it's a very, very long, slow process.”