<div> ?Philosophy, economics, and biology have rarely been so entertaining.”</div><div> ?Matt Ridley, author of <i>Genome</i><br> <br> <div> Paul J. Zak’s proclivity for taking blood samples has earned him a nickname as the ?vampire economist.” But his sanguinary habit is backed by his scientic quest: What if there was a master switch for human behavior? On, and people are loving and generous. Off , and they revert to violence and greed. By studying thousands of blood samples, Zak has pinpointed just such a switch: a brain chemical called oxytocin. Sprinting around the globe and into the human brain,<i>The Moral Molecule</i> is a dazzling narrative as erudite and entertaining as bestsellers like <i>Flow</i>, <i>Drive</i>, and <i>Why We Love</i>.</div></div><br>