"Blanche is written with a terrible authority, the authority that comes from artistic necessity when the writer is compelled to write by his demon, rather than by his agent or promoter"

In this quote, author Paul Bailey is describing the character of Blanche in a play or book. He says that Blanche is composed with a "awful authority," suggesting that she is a strong and commanding character. This authority comes from the "creative necessity" of the author, suggesting that the writer feels a deep and immediate requirement to create this character. This remains in contrast to being motivated by a "agent or promoter," which suggests a more industrial or external influence. Bailey suggests that when a writer is driven by their own inner "demon," the result is a more powerful and authentic character like Blanche.