Duncan Green, author of "How Change Happens." He says of activism: "There has to be a little part of you that acknowledges doubt, ambiguity and uncertainty. You have to have room to change direction."
Ben de la Cruz/NPR
A 2014 photo shows shanty houses on a river bank in Jakarta, Indonesia, where Indonesian President Joko Widodo once pledged to close a fast-growing wealth gap.
Bay Ismoyo /AFP/Getty Images
A campaign called Behind The Brands, led by Oxfam International, is trying to make the inner workings of the 10 biggest food companies in the world more visible to consumers.