1. Inspector Goole
“We don't live alone. We are members of one body. We are responsible for each other. And I tell you that the time will soon come when, if men will not learn that lesson, then they will be taught it in fire and blood and anguish.”

2. Who is Inspector Goole? Goole= Geist; spirit in death.
Inspector Goole isn’t a real inspector; more something like god because he makes them all feel guilty.
His manners are quite extraordinary, “rude and assertive”.
One of the main reasons for his visit to the Birling family is to make them realise what responsibilities they have and that their behaviour has an influence on others.
His views are directly opposite to those of Mr. Birling.

3. About Inspector Goole
The inspector is a very straight forward, no - nonsense kind of person who doesn't get flattered easily nor is his focus easily shifted.
Inspector Goole is a mysterious interrogator who introduces himself as a police inspector. In Act III the characters discover that he is not a police inspector at all even if he did, indeed, inspect them.
According to the stage directions:
“The inspector need not be a big man but he creates at
once an impression of massiveness, solidity and
purposefulness. He is a man in his fifties, dressed in a plain
darkish suit of the period. He speaks carefully, weightily, and
has a disconcerting habit of looking hard at the person he
addresses before actually speaking.”

4. Quotes By Nathan & Graeme
“But after all, it is better to ask for the world than to take it.”
“Public men, Mr. Birling, have responsibilities as well as privileges.”
“We don't live alone. We are members of one body. We are responsible for each other. And I tell you that the time will soon come when, if men will not learn that lesson, then they will be taught it in fire and blood and anguish.”
By Nathan & Graeme