In this chapter, we have looked at what health psychologists do and how they can contribute to our understanding of health and illness. The traditional biomedical model of illness is becoming increasingly redundant because of its emphasis on medical causes, whereas the current big threats to health in the UK are cognitive and behavioural. Dealing with challenges such as widespread obesity and high levels of stress may not best be met through medical solutions such as medication. The best solutions are likely to be found by devising ways to change people’s behaviour at a personal level. In addition, this chapter has explored the role of psychology in understanding the way that people cope with illness.