What makes us happy? Researchers at Harvard have been trying to solve that riddle for 85 years. Now, they think they’ve found the answer. Marc Schulz, associate director of the Harvard Study of Adult Development, joins to tell us more.

Rory Stewart may be the most interesting person you’ve never heard of. He’s an adventurer, writer, politician, and nonprofit leader. He walked across Afghanistan — alone — in the months after 9/11 and wrote a book about the experience that the New York Times called a “flat-out masterpiece”; he then served as a deputy governor in Iraq, held a chair at Harvard, and was elected to British Parliament. Now he’s out with a new memoir called “How Not to Be a Politician.” It’s a funny, candid, and somewhat shocking chronicle of the decade he spent in office. It’s also a book about why our political system feels so broken and what we can do to repair it. Host: Caleb Bissinger Guest: Rory Stewart • To learn more about GiveDirectly, visit givedirectly.org