C.S. Lewis, author of the Narnia books, also wrote a book called The Screwtape Letters, which was and remains very popular with the Christian fraternity.
The book is a series of letters from a senior demon, Screwtape, to his nephew and protégé, Wormwood, who has just graduated from demon Training College. What the letters reveal are all the tricks of the trade so far as devilry is concerned - the ways in which Satan's demons tempt, trick, and otherwise manipulate us so that we are lost to 'the Enemy' (God) and become delicious morsels for 'our Father below', as Screwtape refers to the Devil.
Screwtape's advice to his blundering nephew reveals his own experience at drawing humans to their doom. He explains how we can be tempted to sin, even while we think we are being virtuous. When Wormwood's first 'patient' finds Christianity, Screwtape advises Wormwood thus:
The most alarming thing in your last account of the patient is that he is making none of those confident resolutions which marked his original conversion... I see only one thing to do at the moment. Your patient has become humble. Have you drawn his attention to this fact? All virtues are less formidable to us once the man is aware that he has them, but this is especially true of humility. Catch him at a moment when he is really poor in spirit and smuggle into his mind the gratifying reflection "By jove! I'm being humble," and almost immediately pride - pride at his own humility - will appear. If he awakes to the danger and tries to smother his new form of pride, make him proud of his attempt - and so on, through as many stages as you please. But don't try this for too long, for fear you awake his sense of humour and proportion, in which case he will merely laugh at you and go to bed.
Lewis excels at capturing the labyrinthine and often masochistic patterns of thought into which the religious can get themselves. The cycle described above - of humility, followed by pride in humility, which is smothered by second-order humility, which awakens further pride, and so on - is a nice example.
Lewis's book is filled with pithy reminders of how we can slide into doing wrong - worthwhile reminders whether or not we're religious. The surest way of tempting humans to oblivion, Screwtape tells us, is not to get them to commit spectacular sins, but gently to lull them into the habit of little sins, preferably without them even noticing they are sinning.
It does not matter how small the sins are, provided that their cumulative effect is to edge the man away from the Light and out into the Nothing. Murder is not better than cards if cards do the trick. Indeed, the safest road to Hell is the gradual one - the gentle slope, soft underfoot, without sudden turnings, without milestones, without signposts.
Even if you're not religious, you'll recognize that there is much truth in that.
Screwtape urges Wormwood to encourage the bond between his patient and two breezy, charming and fashionable new friends who are 'rich, smart, superficially intellectual, and brightly sceptical about everything in the world'. To Screwtape's delight, these trendy individuals introduce him to their whole set - 'thoroughly reliable people; steady, consistent scoffers and worldlings who without any spectacular crimes are progressing quietly and comfortably towards our Father's house'. The patient, he hopes, will be seduced away from the Enemy (God) by this sceptical and seemingly-sophisticated bunch. Lewis's real point here, of course, is to warn Christians against hanging out with... er, people like me.
One irony about Lewis's book is that, in producing this exposé of how demons psychologically manipulate people, he engages in a certain amount of psychological manipulation himself. A Christian may find that the siren voices of the demons (whom Lewis seems to think really exist) whispering in their ear are now accompanied by Lewis's own muscular intonations: 'Psst. Don't become friendly with those people - they'll seduce you into sinning!'
Lewis believes that reason favours religious belief. Like many philosophically minded-Christians (such as Keith Ward and Richard Swinburne), he encourages us to think and question. That's the sort of Christian I can respect, the sort that stands in stark contrast to Luther, who insists, 'Faith must trample all reason underfoot', and those evangelicals for whom 'Reason is the greatest enemy that faith has' and 'A free thinker is Satan's slave'.
I'm working on a parody of The Screwtape Letters. My Tapescrew Letters are written by a senior guru/priest to his junior in a fictional religion that nevertheless bears a close similarity to many actual religions. Just as Lewis aimed to take the lid off the activities of the demons, so my book aims to lay bare the psychological manipulation applied by gurus and priests. I'm in fact borrowing Lewis's clever little idea and turning it against him.