#1 New York Times bestselling author A.J. Jacobs undergoes a hilarious, poignant quest to understand what constitutes family—where it begins and how far it goes—in It’s All Relative, a “thought-provoking…delightful, easy-to-read, informative book” (Kirkus Reviews, starred review).

A.J. Jacobs has received some strange emails over the years, but this note was perhaps the strangest: “You don’t know me, but I’m your eighth cousin. And we have over 80,000 relatives of yours in our database.”

That’s enough family members to fill Madison Square Garden four times over. Who are these people, A.J. wondered, and how do I find them? So began Jacobs’s three-year adventure to help build the biggest family tree in history. In It’s All Relative, he “muses on the nature of family and the interconnectedness of humanity in this entertaining introduction to the world of genealogy” (Publishers Weekly).

Jacobs’s journey would take him to all seven continents. He drank beer with a US president, sung with the Mormon Tabernacle Choir, and unearthed genetic links to Hollywood actresses and real-life scoundrels. After all, we can choose our friends, but not our family.

“Whether he’s posing as a celebrity, outsourcing his chores, or adhering strictly to the Bible, we love reading about the wacky lifestyle experiments of author A.J. Jacobs” (Entertainment Weekly). Now Jacobs upends, in ways both meaningful and hilarious, our understanding of genetics and genealogy, tradition and tribalism, identity and connection. “Whimsical but also full of solid journalism and eye-opening revelations about the history of humanity, It’s All Relative is a real treat” (Booklist, starred review).

A.J. Jacobs is the author of Thanks a Thousand, It’s All Relative, Drop Dead Healthy, and the New York Times bestsellers The Know-It-All, The Year of Living Biblically, and My Life as an Experiment. He is a contributor to NPR, and has written for The New York Times, The Washington Post, and Entertainment Weekly. He lives in New York City with his wife and kids. Visit him at AJJacobs.com and follow him on Twitter @ajjacobs.