Disquietingly, one of the senior fellows said to Levitt, “I’m having a hard time seeing the unifying theme of your work. Could you explain it?”

Levitt was stymied. He had no idea what his unifying theme was, or if he even had one.

Amartya Sen, the future Nobel-winning economist, jumped in and neatly summarized what he saw as Levitt’s theme.

Yes, Levitt said eagerly, that’s my theme.

Another fellow then offered another theme.

You’re right, said Levitt, my theme.

And so it went, like dogs tugging at a bone, until the philosopher Robert Nozick interrupted.

“How old are you, Steve?” he asked.

“Twenty-six.”

Nozick turned to the other fellows: “He’s twenty-six years old. Why does he need to have a unifying theme? Maybe he’s going to be one of those people who’s so talented he doesn’t need one. He’ll take a question and he’ll just answer it, and it’ll be fine.”

—THE NEW YORK TIMES MAGAZINE, AUGUST 3, 2003

INTRODUCTION:

The Hidden Side of Everything

Anyone living in the United States in the early 1990s and paying even a whisper of attention to the nightly news or a daily paper could be forgiven for having been scared out of his skin.

The culprit was crime. It had been rising relentlessly—a graph plotting the crime rate in any American city over recent decades looked like a ski slope in profile—

and it seemed now to herald the end of the world as we knew it. Death by gunfire, intentional and otherwise, had become commonplace. So too had carjacking and crack dealing, robbery and rape. Violent crime was a gruesome, constant companion. And things were about to get even worse. Much worse. All the experts were saying so.

The cause was the so-called superpredator. For a time, he was everywhere.