Explanatory Note

We didn’t feel much pressure writing that first book because we genuinely thought few people would read it. (Levitt’s father agreed and said it was “immoral” to accept even a penny up front.) These low expectations liberated us to write about any and everything we found worthwhile. So we had a pretty good time.

We were surprised and thrilled when the book became a hit. As profitable as it might have been to pump out a quick follow-up — think Freakonomics for Dummies or Chicken Soup for the Freakonomics Soul — we wanted to wait until we had done enough research that we couldn’t help but write it all down. So here we finally are, more than four years later, with a second book that we believe is easily better than the first. Of course it is up to you, not us, to say if that is true — or perhaps if it’s as bad as some people feared our first book might be.

If nothing else, our publishers have resigned themselves to our unyielding bad taste: when we proposed that this new book be called SuperFreakonomics, they didn’t even blink.