When Richard Thaler published Nudge in 2008 (with co-author Cass Sunstein), the world was just starting to believe in his brand of behavioral economics. How did nudge theory hold up in the face of a global financial meltdown, a pandemic, and other existential crises? With the publication of a new, radically updated edition, Thaler tries to persuade Stephen Dubner that nudging is more relevant today than ever.