This book provides an overview of the diverse effects of electronic cigarettes (vapes) on human health and their regulatory concerns. It includes a thorough examination of e-cigarettes, covering their historical evolution, chemical composition, metabolomic analysis, health effects, regulatory landscape, and the concerning issue of e-cigarette or vaping-associated lung illness (EVALI) through compelling case studies. As the e-cigarette market constantly evolves, introducing new e-liquid formulations, the book addresses the rising challenges in regulation and monitoring. It also answers critical questions and serves as a reference for e-cigarette researchers and its broader societal implications. This book contains concise practical insights for physicians, toxicologists, and chemists. It is also relevant for public health experts, policymakers, tobacco-dependence treatment providers, tobacco control advocates/activists, health educators, and enthusiasts alike.