There’s an old saying that the true wealth of a man is measured not by the amount of money he has, but rather by the number of friends he has.

By those standards, Verizon IndyCar Series driver Dan Wheldon was a very wealthy man.

It also explains why a new book about Wheldon – “Lionheart – Remembering Dan Wheldon” – is such a touching tribute to those who knew him best: his friends and family.

A devoted son, father, husband and friend, Wheldon seemingly was liked by everyone he came in contact with, from growing up racing go-karts in his native England to earning fame and fortune in the Verizon IndyCar Series, including twice winning the legendary Indianapolis 500.

Even competitive tiffs from on-track racing incidents were typically short and forgettable. Foes simply couldn’t hold grudges against Wheldon for long.

One example was Wheldon’s encounter with Danica Patrick at Milwaukee in 2007. Patrick believed Wheldon chopped down on her car in the race and ruined what she thought might have been a good day.

When she confronted Wheldon after the race, he tried to ignore her and walk away, but Patrick wouldn’t budge. She made sure she had her say – grabbing his arm certainly got his attention. Wheldon listened patiently with little to say. When it was over, Patrick felt they both gained a new mutual respect for each other and became good friends.

When Wheldon died from injuries sustained in a crash at the 2011 season-ending race in Las Vegas, Patrick took it as hard as anyone.

Wheldon deeply valued his friends and others would naturally gravitate to him.

Friend or not, Wheldon was known as a tough competitor on the racetrack, someone who would fiercely defend his actions behind the wheel. If he thought he was right, he wouldn’t back down and would staunchly defend his position – to the point where he could be downright stubborn, at times so much so that others eventually had to intercede.

An example in the book came from Dario Franchitti, one of Wheldon’s closest friends. It wasn’t always that way, however. There was a time the two weren’t speaking. It was so bad, Franchitti wrote, “If we saw one another, we just ignored each other. It was really sad.”

Eventually, Franchitti’s brother, Marino, and a mutual friend, Brent Brush, brought the two together in an “accidental” meeting at a bar. After leaving the two drivers together –neither saying a word to the other – Marino and Brush returned with several glasses filled with Washington Apple shots.

“Brent says that we are all going to take a shot until Dan and I make up,” Franchitti wrote. “Of course, we had a few drinks, we had a hug and that was it. We were fine again.”

Wheldon was not a saint. Earlier in his career, he liked to party. But when he met and married wife Susie, and they had two sons together, you couldn’t find a more devoted father and husband.

“He loved life and taught me how to live each day to the fullest, with no regrets,” Susie wrote in the book.

Among racing notables who share deep and personal memories of Wheldon in “Lionheart” are Patrick, Franchitti, Michael and Marco Andretti, Tony Kanaan, Jenson Button, Chip Ganassi, Sam Hornish Jr., Jimmie Johnson, Dale Earnhardt Jr., Helio Castroneves, Scott Dixon, Bryan Herta and James Hinchcliffe.

There are so many stories in this book – many never previously told – that Wheldon fans will be laughing heartily one minute and shedding tears the next.

“Lionheart,” co-written by Andy Hallbery and Jeff Olson, was released Monday on Amazon.com. The 216-page coffee table-style book is resplendent with dozens of photos of Wheldon at all stages of his life.

The book retails for $74.99, with a portion of the proceeds going to the Dan Wheldon Foundation and Alzheimer’s Association. Click here to order.

Former co-owner of Panther Racing, Mike Griffin, may have put Wheldon’s life and career in the best perspective in his contribution to the book, writing, “He really was the handsome prince who vanquished the infidels, conquered his rivals and returned from the Crusade victorious. Lionheart!”