What role should the tobacco industry have in the e-cigarette market? Should manufacturers contribute to the production of evidence on their products’ safety and efficacy? What are the environmental impacts of e-cigarette use and how should these feature in the discussion? How do e-cigarettes influence smoking-related health disparities? Should physicians recommend switching to e-cigarettes for those who smoke? How broadly applicable is the utility of e-cigarettes? And how should the discourse respond to emerging data? This volume examines the opportunities and challenges of optimizing e-cigarette regulation. The authors describe emerging evidence suggesting that restrictions on e-cigarettes can backfire by nudging consumers toward riskier alternatives. Adopting a social welfare-based approach drawing on economics, policy analysis and regulatory science, the authors then explore how optimal e-cigarette policy might balance risks and benefits, suggesting that it is possibleto leverage the promise of e-cigarettes—a product that is more popular than traditional cessation aids—to protect current and future generations from the smoking-related harms, while still taking important steps to discourage use by young people and those who do not smoke.