What is personality? How can we predict the behaviour based on someone’s present and past behavior? And how can you create change in the behaviour? These are the fundamental questions of personality psychology which many people attempted to answer since humans had the capacity to reflect on themselves and on other people. In this talk, I will focus on the most influential personality theories from Freud to post-modern approaches. We will cover the psychoanalytical perspective, Jungian approach, positive, humanistic, existential, cognitive and finally, the transpersonal theory of individual differences.