I think the success of every novel - if it's a novel of action - depends on the high spots. The thing to do is to say to yourself, 'Which are my big scenes?' and then get every drop of juice out of them. The principle I always go on in writing a novel is to think of the characters in terms of actors in a play. I say to myself, if a big name were playing this part, and if he found that after a strong first act he had practically nothing to do in the second act, he would walk out. Now, then, can I twist the story so as to give him plenty to do all the way through?