Author Ryan Holiday is admittedly not a golf guy. That would be his father, who lives in Kapalua, Maui. But golf and particularly FedExCup No. 3 Rory McIlroy — always a favorite at the Wells Fargo Championship at Quail Hollow — have lately popped up on Holiday’s radar.

That’s because McIlroy, who won THE PLAYERS Championship in March, name-dropped four books during his long, introspective press conference at the Masters four weeks later. Two of them — “The Obstacle is the Way” and “The Ego is the Enemy” — were written by Holiday, who is more known in NFL circles and has immersed himself not in golf but Brazilian jiu-jitsu.

“It’s been really amazing to see the books make their way through professional sports over the last few years, but this one was different because it was probably the first one that impressed my dad!” Holiday, 31, said via email this week. “I know I had heard Cameron McCormick had been recommending it to golfers recently, but really curious to hear about how Rory heard about it.”

McCormick, the well-known coach who works with Jordan Spieth and Kramer Hickok, among others, confirmed he has recommended the book but declined to elaborate.

Was there a Rory bump from the Masters? Hard to tell. The book is already a juggernaut — the No. 1 seller in Philosophy and Movements on Amazon’s Audible. Which is to say McIlroy could have heard about “The Obstacle is the Way” through a number of channels.

A 2014 release, the book preaches the ancient Greek philosophy of stoicism — meeting obstacles with equanimity instead of unhelpful emotion. It has found disciples in, among others, Arnold Schwarzenegger, Chicago Cubs manager Joe Maddon, sideline reporter Michele Tafoya, NFL teams like the 2015 Super Bowl-winning New England Patriots, and LL Cool J.

“Stoicism as a philosophy is really about the mental game,” Holiday said in a Sports Illustrated article in 2015, when the book was taking the NFL by storm.

Given how much time there is to think in golf, no wonder it’s now making its way to the course.

Still, for as much as it resonates with athletes, this is not nominally a sports book. The late tennis player Arthur Ashe and Alabama football coach Nick Saban show up in its pages, but mostly Holiday draws lessons from other leaders and achievers: John D. Rockefeller, Roman emperor Marcus Aurelius, U.S. presidents, Amelia Earhart. All of them, he argues, kept a cool head in lieu of flying off the handle, which dulls thinking and impedes right action.