Bapu Jena was already a double threat: a doctor who’s also an economist. Now he’s a podcast host too. In this sneak preview of the Freakonomics Radio Network’s newest show, Bapu discovers that marathons can be deadly — but not for the reasons you may think.

The social psychologist Robert Cialdini is a pioneer in the science of persuasion. His 1984 book Influence is a classic, and he has just published an expanded and revised edition. In this episode of the Freakonomics Radio Book Club, he gives a master class in the seven psychological levers that bewitch our rational minds and lead us to buy, behave, or believe without a second thought.