"Suppose you wanted to kill people. You would need to know ahead of time how to do it. That part is not too difficult. There are many ways. Some of them are better than others. Most of them have drawbacks. So you use what knowledge you've got, and you invent a new way. You think, and you think, and you think, and you come up with the perfect method. You pay a lot of attention to the setup. Because the perfect method is not an easy method, and careful preparation is very important. But that stuff is meat and potatoes to you. You have no problem with careful preparation. No problem at all. How could you, with your intelligence? After all your training? You know the big problems will come afterward. How do you make sure you get away with it? You use your knowledge. You know more than most people about how the cops work. You've seen them on duty many times, sometimes close-up. You know what they look for. So you don't leave anything for them to find. You go through it all in your head, very precisely and very exactly and very carefully. Just as carefully as you would mark the play card you knew for sure was going to win you a fortune."

“Life is full of decisions and judgments and guesses, and it gets to the point where you're so accustomed to making them you keep right on making them even when you don't strictly need to. You get into a what if thing, and you start speculating about what you would do if some problem was yours instead of somebody else's. It gets to be a habit. It was a habit Jack Reacher had in spades.”

“Suicide bombers are easy to spot. They give out all kinds of telltale signs. Mostly because they're nervous. By definition they're all first-timers.”

“I thought: should I be worried? I was under arrest. In a town where I'd never been before. Apparently for murder. But I knew two things. First, they couldn't prove something had happened if it hadn't happened. And second, I hadn't killed anybody. Not in their town, and not for a long time, anyway.”

“Long experience had taught me that absolute silence is the best way. Say something, and it can be misheard. Misunderstood. Misinterpreted. It can get you convicted. It can get you killed. Silence upsets the arresting officer. He has to tell you silence is your right but he hates it if you exercise that right. I was being arrested for murder. But I said nothing.”

“The protection he relied on for nearly thirty years was based on just two things. The same two things anybody uses to protect against any danger. The same way a nation protects itself against an enemy missile, the same way an apartment dweller protects himself against a burglar, the same way a boxer guards against a knockout blow. Detection and response. Stage one, stage two. First you spot the threat coming in, and then you react to it.”

“People say that knowledge is power. The more knowledge, the more power. Suppose you knew the winning numbers for the lottery? All of them? Not guessed them, not dreamed them, but really knew them? What would you do? You would run to the store. You would mark those numbers on the play card. And you would win...Same for killing people.”