Personality psychology is the study of the person.
For this reason, it remains a tradition in the field to look at various attempts over the last 100-plus yea.
In as much as this is clearly a huge undertaking, it is as much a matter of competing theories as it is of empirical research.
It involves an examination of the effects of genetics, the physical environment, culture, upbringing, trauma, pathology and more.
As such, it is arguably the broadest, most "philosophical," branch of psychology.
Personality psychology is the study of the person