Robert Frank was playing tennis one cold Saturday morning in Ithaca, New York, when his heart stopped. Sudden cardiac arrest–a short-circuit in the heart’s electrical signaling—kills 98 percent of its victims and leaves most of the rest permanently impaired.

Yet two weeks later, Frank was back on the tennis court.

How did this happen? There was a car accident a few hundred yards away from where Frank collapsed. Two ambulances responded but the injuries were minor and only one was needed. The other ambulance, usually stationed five miles away, reached Frank in minutes.

“I’m alive today because of pure dumb luck,” says Frank, a 71-year-old economics professor at Cornell University. Or you can call it a miracle. Either way, Frank can’t take credit for surviving that day. From coincidence or the divine, he got help. Nine years later, he is still grappling with the concept of luck. And, applied to his field of economics, it’s led him into some dangerous territory: Wealth.

Talk about luck and money in the same sentence, he says, and prepare to deal with “unbridled anger.” U.S. Senator Elizabeth Warren of Massachusetts and President Barack Obama were pilloried for suggesting rich Americans should be grateful for what Obama called “this unbelievable American system that we have that allowed you to thrive.” Even referring to the wealthy as “the luckiest among us”–as I did a few months ago–can spark some unhinged reactions.

“There are people who just don’t want to hear about the possibility that they didn’t do it all themselves,” Frank says.

Mild-mannered and self-effacing, he isn’t about to tell the rich “you didn’t build that,” as Obama did (and likely regretted). Frank’s new book, “Success and Luck: Good Fortune and the Myth of Meritocracy,” is a study in diplomacy. Combining memoir with academic research, it’s an earnest argument that all of us—even the rich—would be better off recognizing how luck can lead to success.

You did build that—mostly

First, Frank wants to make clear, you did build that–for the most part. Bill Gates, Warren Buffett, or any other wildly successful person didn’t merely get lucky. “It’s clear that most of the biggest winners in the marketplace are both extremely talented and hardworking,” he writes.

In fact, a prerequisite of success in many fields may be a strong refusal to believe in luck. The idea of “making your own luck” is great motivation, while nothing can kill your drive more than suspecting the game is rigged. The reality however is that luck does matter. It’s hard to see in your own life if things are going well: Frank says it’s like running with a tailwind, as opposed to a headwind.

It’s easier to see in aggregate statistics: In professional hockey leagues, researchers have noticed, 40 percent of players are born in the first three months of the year, while just 10 percent were born in October, November and December. The reason must be that Jan. 1 is the birth date cut-off for youth hockey teams, Frank says, and older kids end up getting a lifelong advantage over their peers. A similar phenomenon has been found among CEOs. There are a third fewer chief executives born in June and July than you’d expect by chance. Kids born in the summer tend to be the youngest in their classes starting school.