The following 25 Screwtape Letters quotes provide an insightful summary of The Screwtape Letters Play by Max McLean:

1. A healthy dose of “real life”…was enough to show him that all “that sort of thing” just couldn’t be true (p. 4)
2. One of our great allies at present is the Church itself. Do not misunderstand me. I do not mean the Church as we see her spread but through all time and space and rooted in eternity, terrible as an army with banners. That, I confess, is a spectacle which makes I our boldest tempters uneasy. But fortunately it is quite invisible to these humans. (p. 6)
3. What this will actually mean to a beginner will be an effort to produce in himself a vaguely devotional mood in which real concentration of will and intelligence have no part. (p. 11)
4. It is funny how mortals always picture us as putting things into their minds: in reality our best work is done by keeping things out. (p. 12)
5. So do not allow any temporary excitement to distract you from the real business of undermining faith and preventing the formation of virtues (pp. 14-15)
6. And how disastrous for us is the continual remembrance of death which war enforces. One of our best weapons, contented worldliness, is rendered useless. (p. 16)
7. Their nearest approach to constancy, therefore, is undulation—the repeated return to a level from which they repeatedly fall back, a series of troughs and peaks…In the first place I have always found that the Trough periods of the human undulation provide excellent opportunity for all sensual temptations, particularly those of sex. (pp. 22-25)
8. An ever-increasing craving for an ever-diminishing pleasure is the formula…get the man’s soul and give him nothing in return. (p. 26)
9. A moderated religion is as good as no religion at all–and more amusing (p. 27)
10. He will be silent when he ought to speak and laugh when he ought to be silent. (pp. 28-29)
11. All mortals tend to turn into the thing they are pretending to be. This is elementary. (p 29)
12. And while he thinks that, we do not have to contend with the explicit repentance of a definite, fully recognised, sin, but only with his vague, though uneasy, feeling that he hasn’t been doing very well lately.” (p. 34)
13. You are anxious to be able to report spectacular wickedness…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. (p. 36)
14. Indeed the safest road to Hell is the gradual one (p. 36)
15. The great thing is to prevent his doing anything. As long as he does not convert it into action, it does not matter how much he thinks about this new repentance. (p. 38)
16. Your patient has become humble; have you drawn his attention to this fact? (p. 39)
17. This has largely been effected by concentrating all our efforts on gluttony of Delicacy, not gluttony of Excess. “All I want is…a cup of tea [etc.]…done properly” (pp. 48-49)
18. The whole philosophy of Hell rests on recognition of the axiom that one thing is not another thing, and, specially, that one self is not another self. (p. 51)
19. As a result we are more and more directing the desires of men to something which does not exist—making the role of the eye in sexuality more and more important and at the same time making its demands more and more impossible. (p. 59)
20. He is there daily meeting Christian life of a quality he never before imagined and seeing it all through and enchanted glass because he is in love. He is anxious (indeed the Enemy commands him) to imitate this quality. Can you get him to imitate this his defect in his mistress and to exaggerate it until what was venial in her becomes in him the strongest and most beautiful of the vices–Spiritual Pride? (p. 70)
21. Avail yourself of the ambiguity in the word “Love”: let them think they have solved by Love problems they have in fact only waived or postponed under the influence of the enchantment. (pp. 75-76)
22. Once he accepts the distraction as his present problem and lays that before the Enemy and makes it the main theme of his prayers and his endeavours, then, so far from doing good, you have done harm. (p. 79)
23. I sometimes wonder if you think you have been sent into the world for your own amusement! (pp. 88-89)
24. They, of course, do tend to regard death as the prime evil and survival as the greatest good. But that is because we have taught them to do so. Do not let us be infected by our own propaganda! (p. 83)
25. He has done everything his duty demanded and perhaps a bit more. (p. 89)