The term fortology refers to the origins of strength, and is used as an alternative to positive psychology. The purpose of the review is to highlight extant knowledge and the research potential of the field. In the first section of the review, positive emotions are considered as lived experiences, and their significance explained with reference to Fredrickson's Broaden-and-Build Theory. Both short-duration and longer-term effects of positive emotions are reviewed. The contributions of humour, optimism and gratitude to positive emotions are considered, as are ways of increasing the frequency of positive emotions. The second section of the review considers positive emotionality, which is the trait that forms the background to positive emotions. Finally, an overview is given of the role of genetics, the behavioural approach system, natural killer cells and dopamine — each of which plays a part in subjective experiences.