Background and challenges to implementation:
The e-cigarette is touted as a disruptive technology that could make combustible cigarettes obsolete. The product, its science and politics though are controversial.

Intervention or response:
Published journal articles, reports and conference presentations on e-cigarettes were located using PubMed, plus conference, industry and other websites. These were critically reviewed.

Results and lessons learnt:
A number of contentious issues regarding e-cigarettes were identified:
Its use is recommended by some public health bodies (UK Royal College of Physicians) but not by others (World Health Organization).
The product may not be fit-for-purpose, with low consumer acceptance. In 2016, 72% of those who had tried an e-cigarette in the UK no longer used it, A majority of users combined smoking with vaping and are thus unlikely to obtain significant health benefits.
E-cigarettes do not deliver nicotine as rapidly and effectively as combustible cigarettes. Vaping was reportedly less "satisfying" than smoking. The development of 'heat not burn' and other novel products by the industry is testimony to its deficiencies.
E-cigarettes have divided the anti-smoking community, with some regarding the tobacco companies as essential partners while others shun it.
Finally, the profit-driven multinationals regard affluent countries as the prime market for novel products, while simultaneously seeking to maintain and expand the conventional cigarette market in poor continues.

Conclusions and key recommendations:
There are many unresolved scientific, policy and political concerns about the role of e-cigarettes in tobacco control.
A continued focus on supply and demand reduction instead of harm reduction is the best option for low-income countries.