Hans Jürgen Eysenck was a German-born British psychologist. He is best remembered for his work on intelligence and personality, although he worked on other issues in psychology. At the time of his death, Eysenck was the most frequently cited living psychologist in the peer-reviewed scientific journal literature.

Personality psychology is a branch of psychology that examines personality and its variation among individuals. It aims to show how people are individually different due to psychological forces. Its areas of focus include:Describing what personality is Documenting how personalities develop Explaining the mental processes of personality and how they affect functioning Providing a framework for understanding individuals