(To receive weekly emails of conversations with the world’s top CEOs and decisionmakers, click here.) There’s an endearing scene early in Rajiv Shah’s new book, Big Bets. It’s 2010, and he has just been sworn in, at age 36, as head of the multi-billion-dollar U.S. agency that oversees humanitarian and development aid around the world.…

The Rockefeller Foundation’s Rajiv Shah on How to Tackle the World’s Biggest Challenges