The song “We Are Family” has taken on new meaning for A.J. Jacobs.

The author has spent the past four years delving into the world of genealogy, researching the ways in which all humans on the planet are connected to one another.

His new book, “It’s All Relative: Adventures Up and Down the World Family Tree,” was published Nov. 7, and he hopes the book helps people feel connected in what has become such a divisive time.

Author A.J. Jacobs

To help with that goal, he held a Global Family Reunion where hundreds of people came to meet their cousins from around the world (and yes, Sister Sledge performed). It was one of countless experiences Jacobs had while putting together the book.

He spent time in Utah, a place he calls “the mecca of genealogy.”

“I feel so lucky the Mormon church and Family Search were so supportive of my project,” Jacobs said. “They helped me with my research, and I even got to sing with the MoTab at their rehearsal.”

He’s returning Tuesday, Nov. 14, at 7 p.m. to The King’s English Bookshop for a meet-and-greet.

“I’m looking forward to catching up with some of my cousins,” he said.

The Tribune caught up with Jacobs ahead of his visit and chatted about everything from adulterous affairs to world peace.

What inspired this book?

It started about four years ago when I got an email saying, “You don’t know me, but I’m your eighth cousin.” I figured he was going to ask me to wire $10,000 to Nigeria, but it turned out he was legitimate. He was one of this group helping to build the biggest family tree in history — millions of people in dozens of countries, united on the same family tree. It blew my mind.

Genealogy had always seemed a little stodgy to me; it was along the lines of needlepoint — interesting to some, but not my cup of tea. But it’s one of the most fascinating areas in the world; it’s exploding with millions of people searching. It involves everything from politics to race relations to raising kids. I knew this has got to be the topic of my next book.

Why are people so obsessed with genealogy?

Partly because this is the golden age of genealogy with the access to information; it’s astounding what you can get. You have DNA-testing services, amazing websites with these massive trees you can collaborate on online, TV shows, cruises, old newspapers (it’s amazing what you can find in old newspapers). There is no way to hide the skeletons in our family closet. I recently just found out that my second cousin three times removed was a big part of the Teapot Dome Scandal, and there was blackmailing and an adulterous affair. It’s very exciting.

Why is it important people feel connected in this way?

On a very basic level, we wouldn’t exist without these people. Think of how much had to go right for every one of us to exist; it makes you more grateful. You have two parents, four grandparents, then eight; by 10 generations, you have hundreds of thousands of people who had to hook up and do their business with each other for you to exist. So I think that fascinates people. It’s interesting, the basic idea, it’s fascinating to see what people focus on. It shows a lot about their family. You may be a descendent from a Mayflower passenger, but I’m sure they had plenty of embezzlers and roustabouts and plenty of people who were not so fancy. It’s important to remember we all come from mixed backgrounds.

How did you filter through so many stories?

I had enough material to write eight to 10 books. I went with the ones that fascinated me the most. There were a lot I couldn’t get out of my mind, such as the story of Michael, a Mormon man who found out after his dad’s passing he and his eight siblings were from eight different fathers. In one sense, it was inspiring he was so forgiving of his mother, who obviously had a bunch of different lovers, and whose father, who wasn’t his biological father, loved and treated the kids like they were — that guy’s a hero.

How do you define family?

I like the idea of a very broad definition of family, since science has proven that everyone on Earth is a cousin, and probably about 70th cousin is the farthest we have on Earth. I like to apply the definition broadly. We are all family, but you can’t buy a birthday gift for all 7 billion, so I focus on my immediate family in that sense. But when someone cuts me off on the highway, I like to think we share a 10th great-grandfather, and I don’t want to embarrass our shared relative, so I try to act kindly.

I love your writing style. I feel like we are friends after reading this. In fact, I guess we’re cousins. But you swing so gracefully from goofball to deeply introspective. What inspires your style?

Partly it’s my dad. He’s a goofball and he loves learning. That was my first book, because he’s a lawyer, and he wanted to learn about everything in the world, so he started reading the Encyclopedia Britannica. He made it to Bolivia. I thought maybe I should try to finish it. I got that mix from him; as a writer, I love to write conversationally, like I’m telling a story over a dinner table. It’s not the only way to write. I love writers who are literary and have a flair for beautifully constructed sentences.

What do you hope readers take away from this book?

I hope they have a good time, I hope they feel like they are my cousin and friend at the end. I hope they get some amazing stories, I hope they learn a lot about these amazing revolutions in the DNA world and massive online family trees. I also hope they are reminded that we all are one big family. Having that mindset makes a difference. I don’t think world peace is going to break out, but it’s going to help us in the right direction just a little. There was a great Harvard study last year. The scientists showed a group of Palestinians and Israelis how closely related they were. They showed each other more kindness. That’s a wonderful finding and one that can have a big impact.

A.J. Jacobs reading and signing

When • Tuesday, Nov. 14, at 7 p.m.

Where • The King’s English Bookshop, 1511 S. 1500 East, Salt Lake City

What • Places in the signing line are reserved for those who purchase the book from The King’s English for $29.99. Order by calling the store at 801-484-9100 or online at www.kingsenglish.com. Please specify if you will be attending the event and if you want your book personalized.

It’s All Relative: Adventures Up and Down the World’s Family Tree

By A.J. Jacobs

Simon & Schuster

352 pages

$27
(Courtesy photo) The cover of A.J. Jacobs' latest book, “It’s All Relative: Adventures Up and Down the World Family Tree.”