It so happened that we had a very good math teacher, who was a Communist. I remember having learned from him something that I never forget: the rule of nines. A simple point: you add up the numerals in a number, and if the original number was divisible by nine, then the sum of the figures also is. For instance, you take a number like 243. Two and four and three is nine. Therefore, 243 must be divisible by nine. Actually it is nine times 27. The rule is interesting because it’s so simple. What was really interesting to us ten-year-olds is that our math teacher proved it. The proof is not terribly difficult, but it was one of the first simple and not quite obvious mathematical proofs that I encountered.

The closest to inspiration was my beloved fifth grade teacher, Mrs. Ponti, who I’m delighted lived long enough to get that book’s dedication. I exchanged Christmas cards with her for the rest of her life. She was a wonderful woman. I think the main way she inspired was by respecting students’ interests. She herself knew very little science. Science was not formally taught at all, as far as I can remember, at grade school level. She realized there were a group of us who were interested in science, so she would let us sit by ourselves in the back of the classroom once a week for a couple hours, and she got books for us and discussed science. So I suppose she was a very good model for good students.

In high school, I had a teacher who influenced me greatly, Miss Olive J. Williams, and she was versatile in music, and I wanted to be like her. She exposed me to the world of classical music. Before then, I had never heard classical music. She exposed me also to the great composers of the world, as well as black performers, which I didn’t know about at the time: Marian Anderson, Paul Robeson, Roland Hayes and Dorothy Maynor and others.

I had lots of teachers encourage me. And I still know some of them, my high school teachers. But one of them encouraged me. She said, “Well, what do you want to do?” I said, “I want to be a doctor.” And she asked me where I wanted to go to school, and so I named all the Florida public universities which seemed within reach, financially. And she said, “Well, maybe you ought to apply to Duke, and maybe you’ll get a scholarship.” And I did both those things. I applied and got a scholarship. Her name is Wendy Tellone, and she’s still involved in public school teaching. I think she’s still in Florida.

And the most fulfilled, centered, grounded, happy people I know are people who made the choice to be part of an effort to actually make the world a better place. ... I would say, to me, the path of least regrets is to at least make a short-term commitment to say, “Let me work to make a real difference in the world.” The worst that could happen is you decide to move into something else later, but you’ll always take with you what you’ve given and what you’ve gained through that experience.

I applied to one firm in every sector. This was the most half-hearted job search. “I’ll apply for that management consulting firm and this investment bank…” and I applied for five jobs altogether, because my heart wasn’t in it. And thankfully… I’m so glad I didn’t get any of those big jobs! Because that made this decision easier.

The Fountainhead , I think, pretty much saved me in the initial years of Teach For America. I loved that book, but I’m not sure books were the seminal thing that guided my path. ... I think it was sort of about “the creator against the world,” and I was probably feeling at that point that I was up against lots of boulders, to pull off the big idea of Teach For America.