Holiday, a university dropout, previously handled public relations for American Apparel during a period when its founder was accused of rape. He later drew negative media attention for his first book, "Trust Me, I'm Lying: Confessions of a Media Manipulator", which detailed how to dupe the press.
But his subsequent works, including "The Daily Stoic", "The Obstacle Is the Way", "Ego Is the Enemy" and "Stillness Is the Key", have found a vast audience. The New York Times described him as the unlikely poster boy for stoicism, an ancient philosophy that holds that while we do not always control what happens to us, we always control how we respond.
Holiday has said that stoicism transformed his own approach to life. His favourite quote from the stoics, he has noted, is from the Roman emperor Marcus Aurelius: "Waste no more time arguing what a good man should be. Be one." Today, according to the profile, Holiday's focus is on being good in action.
Golfer Rory McIlroy has credited stoicism with helping him maintain his high ranking on the PGA Tour. The books have also inspired figures such as Arnold Schwarzenegger and Tom Brady.