What does the word ‘person’ mean? The question has been a theme of Western thought for two thousand years. Around the year 500, Boethius gave a definition that remained standard, though not unchallenged, for over a millennium, although at present little is heard of this meaning. The Logic of Human Personality shows how the ancient definition of person remains useful today and explains how it happened to fall into disuse. The history of the word ‘person’ begins in ancient Rome and Greece, a century before the present era.There is a survey of some of the Latin and Greek writers who used this word in ancient and patristic times bears out the hypothesis that Greek root of the word had a more physical emphasis than the Latin, and that the loner had about it the air of theatrical role and legal agency. These two emphases have remained in the word as it is used at present; different thinkers tend to emphasise each and thus to draw from them different conclusions. Against Mill and others who have found Aristotle’s categories unsatisfactory, The Logic of Human Personality argues that in fact they are useful for much psychological and anthropological research today, particularly in the intercultural field.