Who gives Max the Golden Key in the novel, The Amazing Adventures of Kavalier & Clay?

The Golden Key is a key that a man who frees Max Mayflower, gives to him, while on his deathbed. Max Mayflower, in turn, when shot, gives the Golden Key to Tom Mayflower. The Golden Key is a comic-book object, which is a metaphor for the freeing of the oppressed. In the comic-book, there is an actual League of the Golden Key organization. This metaphor is used when Joe tries to free his brother Thomas and is used again when Sammy decides to free himself from his loveless marriage.