The founders of Juul, the company that invented the namesake product, said they wanted to have a positive impact on the world by helping longtime smokers quit cigarettes in favor of their cooler, tech-ier, less carcinogenic product. They hoped this mission would help protect them from the legal and political pressure and public scorn that had been heaped on the major cigarette makers for decades. Juul’s co-founders, Adam Bowen and James Monsees, met as product design graduate students at Stanford University and set out to challenge the tobacco industry in the mid-2000s by designing an electronic cigarette as their final thesis project. As Lauren Etter recounts in “The Devil’s Playbook,” her deeply reported and illuminating book about the company’s ascent, their stated focus on reducing harm to smokers turned out to be little more than a clever marketing line attached to an aggressive company with ambitious goals for turning a profit.