[Cronos]

There are a number of additional themes running in the Screwtape letters like

1. After the dedication, Lewis has two quotes, both mocking the devil: one by Martin Luther and the other by Thomas More. The great hero of the Protestant Reformation Luther, alongside St. Thomas More, a Catholic heroes of the Counter-Reformation. And BOTH have the same theme of mocking the devil
2. The entire book elaborates free will.
3. Of course the key theme is that we can fall into two extremes that are error-prone: denying demons exist or getting obsessed with them

[HarleyD]

There are a number of additional themes running in the Screwtape

That's true. One has to keep in mind that CS Lewis was Angelican. That doesn't mean there are gems of inspirations we can get from his writings. After all, Augustine was Catholic and I like his works. ;O)

[betty boop]

After the dedication, Lewis has two quotes, both mocking the devil....

Might as well put up the quotes!

"The best way to drive out the devil, if he will not yield to texts of Scripture, is to jeer and flout him, for he cannot bear scorn." — Martin Luther

"The devil . . . the prowde spirite ... cannot endure to be mocked." — Thomas More

Thank you so very much for your insights, Cronos — especially your points (2) and (3):

"Of course the key theme is that we can fall into two extremes that are error-prone: denying demons exist or getting obsessed with them."

Seems to me demons do exist; and the best way to deal with them is as Luther and More direct: Simply dismiss them by ridicule. This saves one from "obsessing" about them....

Free will in action.