Personality is a psychological construct aimed at explaining the wide variety of human behaviours in terms of a few, stable and measurable individual characteristics. In this respect, any technology involving understanding, prediction and synthesis of human behaviour is likely to benefit from Personality Computing approaches, i.e. from technologies capable of dealing with human personality. The presentation introduces a conceptual model underlying the three main problems addressed in the field, namely Automatic Personality Recognition, Automatic Personality Perception and Automatic personality Synthesis. Furthermore, it shows a few examples of how personality traits can be inferred from different types of behavioural evidence.