With so many social challenges facing our world, trying to effect change feels daunting. The problems are complex, the politics murky, and the players innumerable. Yet, every day there are regular heroes making a significant impact on our most intractable social issues. “Can’t Not Do” is a catchphrase for the urge that captures the heart of effective social change agents—explaining, in their own words, their passion and drive: “I can’t not do this.” “It’s not that I can do this, it’s that I...