Abstract Electronic nicotine delivery systems (ENDS), also known as electronic cigarettes or e-cigarettes, have become an increasing share of the nicotine product market. Throughout many countries, such as Canada, Australia, the United Kingdom, and the United States, the prevalence of e-cigarette use has risen rapidly over the past 20years. Not only has its use increased, but technological advancements of e-cigarettes have also been emphasized. As such, a better understanding of the successive e-cigarette generations, which have increased complexity and abundance of personalized applications and e-liquids, is warranted. Also, the use of e-cigarettes is associated with both underlying risks and benefits of which are critical to understand when considering the overall demographic of e-cigarette users. Here, we review the various generations and typologies of e-cigarettes, the prevalence of use, the associated risks and safety issues, the clinical characteristics of these products, and their potential as tobacco cessation and harm reduction interventions. In general, there is mostly anecdotal evidence regarding the success of e-cigarettes for smoking cessation and more research must be conducted; however, select studies provide evidence for the use of these devices through controlled experimental design.