It's not how much money we make that ultimately makes us happy between nine and five. It's whether or not our work fulfills us. Being a teacher is meaningful.

The Tipping Point is the biography of an idea, and the idea is very simple. It is that the best way to understand the emergence of fashion trends, the ebb and flow of crime waves, or, for that matter, the transformation of unknown books into bestsellers, or the rise of teenage smoking, or the phenomena of word of mouth, or any number of the other mysterious changes that mark everyday life is to think of them as epidemics. Ideas and products and messages and behaviors spread just like viruses do.

The single most important thing a city can do is provide a community where interesting, smart people want to live with their families.

When writing, you can't break physical rules. You can't have people come back from the dead. That's cheating. I am a kind of narrative fundamentalist in many ways.

There are some people, who I'll charitably call snobs, who are dismissive of any conversation that doesn't begin with the full level of complexity. That's just not how the world works.

And my advice for college graduates is don't reflexively give money to your alma mater, something particular to Americans that I find extraordinary. Take Princeton, for example - it has more money on a per capita basis than any educational institution in the history of educational institutions. There is no scenario where it can spend all the money its endowment generates every year. If there is anyone who gives a single dollar to Princeton, they have completely lost their mind. I will say that without reservation.

David Epstein, the author of the best book on athletics in recent memory - "The Sports Gene" - wrote to me to say that he thinks I'm being overly generous. He points out that, for years, there used to be an "all-star challenge" on television, in which the best professional athletes from a variety of sports competed in a kind of makeshift decathlon.