I know it sounds hard to believe, but habits laid down by our ancestors persist even after the conditions that created those habits have gone away.

The Rule of 150 says that congregants of a rapidly expanding church, or the members of a social club, or anyone in a group activity banking on the epidemic spread of shared ideals needs to be particularly cognizant of the perils of the bigness. Crossing the 150 line is a small change that can make a big difference.

What happens when two people talk? That is really the basic question here, because, that's the basic context in which all persuasion takes place.

My highest compliment is when someone comes up to me to say, "My 14-year-old daughter, or my 12-year-old son read your book and loved it." I cannot conceive of a greater compliment than that - to write something that as an adult I find satisfying, but also that manages to reach a curious 13- or 14-year-old.

Nothing frustrates me more than someone who reads something of mine or anyone else's and says, angrily, 'I don't buy it.' Why are they angry? Good writing does not succeed or fail on the strength of its ability to persuade. It succeeds or fails on the strength of its ability to engage you, to make you think, to give you a glimpse into someone else's head—even if in the end you conclude that someone else's head is not a place you'd really like to be.

Happiness, in one sense, is a function of how closely our world conforms to the infinite variety of human preference.

The sense of possibility so necessary for success comes not just from inside us or from our parents. It comes from our time: from the particular opportunities that our place in history presents us with.