—Helen Fisher, author of Why We Love

 
“Paul Zak tells the remarkable story of how he discovered and explored the biochemistry of sympathy, love and trust with the narrative skill of a novelist. Philosophy, economics and biology have rarely been so entertaining.”

—Matt Ridley, author of Genome

“An ancient mammalian molecule prods us to bond with others. Paul Zak offers a most engaging account of this important discovery, bound to overthrow traditional thinking about human behavior, including economics and morality.”

—Frans de Waal, author of The Age of Empathy

 
“Paul Zak's investigations into the best things in life are inspired, rigorous, and tremendous fun. We need more daring economists like him.”

— Tyler Cowen, author of An Economist Gets Lunch

“Zak has always been intrepid, with a sense of innocent but parsimonious wonder, and as a result his book on rather severe issues is nevertheless fresh—and moral.”

—Lionel Tiger, author of God’s Brain