I seldom get to work before 10 A.M. and then I never write more than four hours. Indeed, two hours would usually be more like it, two hours of actual composition, that is. I usually begin a writing period by answering letters. As with everything I do, this would seem contrary to the practice of everyone else, but I warm up in that fashion. For example, at this moment the time is 11:45 A.M. I have done nothing thus far this morning but write letters. After this one I will presumably work on my 11th novel, and I will surely work no longer than 2:30. Writing is a very intense experience for me, but the strain is too great to maintain for long. Interestingly enough, this is true only when the novel is going well, is for me truly an alternative to life. When I have no conviction I can write all day!
The New York Times, April 6, 1980