In Fahrenheit 451, what role does Professor Faber play in Montag's development as a character, and who is Professor Faber?

Apart from Clarisse, Professor Faber may be
the most important influence on Montag in the novel. He guides Montag through his
transformation, encouraging the protagonist to explore the books he's
recovered. At one point, Faber gives Montag a transmitter that fits in
his ear, so that they can have continuous communication. Unfortunately, Montag becomes
overconfident and begins behaving recklessly, reading poetry to his wife and her
friends, despite Faber's warnings.

Shortly thereafter,
Montag is called to burn his own house. During the confrontation, Captain Beatty
discovers the Seashell (transmitter), and Montag kills him and flees. He runs straight
to Faber, who sets him on a path to freedom from society. He introduces Montag to a
group of outsiders who hold great works of literature alive in their minds.
One might argue that Faber, along with Clarisse, "saves" Montag from the
crippling alienation and isolation of the society in the
novel.