I have never carried a book with me as I want to be alert and ready even thou bordom does set in. I have dozed off from eye and mental fatigue and have occasionaly woke up only to have deer within range. A few years back that happened in Kansas and the deer in range was a 150 class 10 point. Because I was caught sitting down I was never able to get up and take the shot. But it seems the older I get the harder it is not to doze off on an all day sit.