In the mid 21st century, humans finally established a small community on Mars. The Martian colony grew slowly over its first 50 years. There were substantial technical challenges to living in the artificial biospheres. Early colonists had to accept significant restrictions because of the harshness of the environment, and the limited shared physical space. However, by 2116, the community was starting to relax its initial strictures. There was a growing community of young, native Martians. Technology was more robust. Some of the initial strict rules were being reconsidered and debated in the Martian parliament. One question, tabled for late 2116, was whether it should be permissible to grow tobacco. Smoking had not been an option for the initial colonists. Only non-smokers were allowed to travel because of the dangers of fire during the long journey from Earth and in the first generation of domes. But now the atmospheric regulators were stable enough to cope with combustion of plant matter, while the community had sophisticated mechanisms to prevent dangerous fires. Should Martians be allowed to smoke? Several of the papers in this issue address the questions that our hypothetical Martian community would face. One way of casting the debate over tobacco policy sees it in terms of a trade-off between wellbeing and autonomy. Those in favour of banning cigarettes empasise the significant improvements in people's health and wellbeing from not smoking (see feature article by Kalle Grill and Kristin Voigt page 293 ). Those opposed to such a ban, draw on traditional liberal principles to reject any hard paternalistic restriction to individual freedom on the basis of concern for the good of the individual (see response by Jessica Flanigan page 305 ). Grill and Voigt take a nuanced view. They point out the …