No single theory of personality can adequately explain the full function of human behaviour. Psychodynamic approaches often come under a lot of criticism as they fail to be explicit about the underlying bases of the theory. Cognitive theories are not very comfortable with explaining emotions and behavioural theories have difficulty explaining the mechanisms of improvements. It has become quite clear in the field of Psychology, and to some Psychologists like Windy Dryden (Individual Therapy) explicitly clear that there is a missing linkand that somewhere amongst the mass of theories on personality, the answer is staring them in the face. These Psychologists often practice a form of Psychology called Eclectism, which takes a little out of each theory and unites it during therapy with a client. You can't use this sort of therapy as a theory however because all the Eclectic Psychologist is doing is ignoring the fundamental ideological underpinnings of the particular theories he is using and taking the parts relevant to their client in therapy This essay will explore one of the possible combinations of theories on personality and explain how it can be applied in practical therapy. Eysenkes theory of biological bases in behaviour is the base of this essays approach. It provides the rules within which the other two personality theories (Kellys Personal Construct Theory and Maslows Hierarchy of Human needs) can function. Using Eysenkes theory on extravert and introvert behaviour it is possible to determine from birth, very general traits about which a person is willing to work within (aggression, anxiety tolerance and sociability etc) which is where this essay believes Kelly slightly misunderstands this concept and defines it as his Range Corrollary. Really the person is experiencing a fundamental shift from Extravert behaviour or thinking to Introvert or vice versa which causes slight unease and...