Let's look at the four main themes:
The consequences of the Birlings' actions highlight Priestley’s ideas on social responsibility - do we look after one another in society?
The difference between the younger and older characters' reactions to Eva Smith's death shows how Priestley viewed different generations . He viewed the younger generation as hope for the future and this is why both Sheila and Eric learn a lesson from the Inspector.
How the male characters behave towards the females in the play highlights important points on gender and inequality.
Class issues are also dealt with by having a middle-class family involved in the death of a working-class girl.
J B Priestley explored these themes in a lot of his work. They are political in nature and are still relevant today.