For obvious reasons, C. S. Lewis’s book That Hideous Strength has never received the praise it deserves.  I cannot agree with A. N. Wilson’s assertion, in his entertaining but tendentious biography of Lewis, that the novel is too long.  For me, in fact, it ends too soon: its principal flaws are that the descent of the Oyeresu is described too briefly, and that the reconciliation of Mark and Jane Studdock is left to the imagination.
Most of all, I should like to have heard more from Merlinus Ambrosius, that is, Merlin, who irrupts into the book half-way through. The enemy planned to use him as a tool for evil, but he turns out to be a Roman Christian gentleman who puts himself at the service of Ransom, the Director of St Anne’s and true Pendragon in the line of Arthur. For my money, the best parts in the story are those in which Merlinus is commenting on the mid-twentieth century world into which he has been revived, after his long sleep beneath the turf of Edgestow.
Sometimes his observations pertain only to the stranger manners of the latter days:
“Sir,” said Merlin, in answer to the question which the Director had just asked him, “I give you great thanks. I cannot, indeed, understand the way you live, and your house is strange to me. You give me a bath such as the Emperor himself might envy, but no one attends me to it: a bed softer than sleep itself, but when I rise from it I find I must put on my own clothes with my own hands as if I were a peasant. I lie in a room with windows of pure crystal so that you can see the sky as clearly when they are shut as when they are open, and there is not wind enough within the room to blow out an unguarded taper; but I lie in it alone, with no more honour than a prisoner in a dungeon. Your people eat dry and tasteless flesh, but it is off plates as smooth as ivory and as round as the sun. In all the house there is warmth and softness and silence that might put a man in mind of paradise terrestrial; but no hangings, no beautified pavements, no musicians, no perfumes, no high seats, not a gleam of gold, not a hawk, not a hound. You seem to me to live neither like a rich man nor a poor one: neither like a lord nor a hermit. Sir, I tell you these things because you have asked me. They are of no importance.”
Morals, however, he recognises as infinitely more important than manners:
She did not understand the words: but Dimble did, and heard Merlin saying in what seemed to him a rather strange kind of Latin: “Sir, you have in your house the falsest lady of any at this time alive.” 
And Dimble heard the Director answer in the same language. Sir, you are mistaken. She is doubtless like all of us a sinner: but the woman is chaste.” 
“Sir,” said Merlin, “know well that she has done in Logres a thing of which no less sorrow shall come than came of the stroke that Balinus struck. For, sir, it was the purpose of God that she and her lord should between them have begotten a child by whom the enemies should have been put out of Logres for a thousand years.”
“She is but lately married,” said Ransom. “The child may yet be born.” 
“Sir,” said Merlin, “be assured that the child will never be born, for the hour of its begetting is passed. Of their own will they are barren: I did not know till now that the usages of Sulva [the moon] were so common among you. For a hundred generations in two lines the begetting of this child was prepared; and unless God should rip up the work of time, such seed, and such an hour, in such a land, shall never be again.” 
“Enough said,” answered Ransom. “The woman perceives that we are speaking of her.” 
“It would be great charity,” said Merlin, “if you gave order that her head should be cut from her shoulders; for it is a weariness to look at her.”
Merlinus is surprised, too, that the little company at St Anne’s do not  see the justice of treating self-sterilization as a capital offence:
“The Pendragon tells me,” he said in his unmoved voice, “that you accuse me for a fierce and cruel man. It is a charge I never heard before. A third part of my substance I gave to widows and poor men. I never sought the death of any but felons and heathen Saxons. As for the woman, she may live for me. I am not master in this house. But would it be such a great matter if her head were struck off? Do not queens and ladies who would disdain her as their tire-woman* go to the fire for less? Even that gallows bird (cruciarius) beside you – I mean you, fellow, though you speak nothing but your own barbarous tongue; you with the face like sour milk and the voice like a saw in a hard log and the legs like a crane’s – even that cutpurse (sector zonarius), though I would have him to the gatehouse, yet the rope should be used on his back, not his throat.”
He finds the changes in geo-politics, too, hard to grasp:
“Mehercule!” he cried. “Are we not going too fast? If you are the Pendragon, I am the High Council of Logres, and I will council you. If the Powers must tear me in pieces to break our enemies, God’s will be done. But is it yet come to that? This Saxon king of yours who sits at Windsor, now—is there no help in him?”
“He has no power in this matter.”
“Then is he not weak enough to be overthrown?”
“I have no wish to overthrow him. He is the king. He was crowned and anointed by the Archbishop. In the order of Logres I may be Pendragon, but in the order of Britain I am the King’s man.”
“Is it, then, his great men – the counts and legates and bishops – who do the evil and he does not know of it?”
“It is – though they are not exactly the sort of great men you have in mind.”
“And are we not big enough to meet them in plain battle?”
“We are four men, some women, and a bear.”
“I saw the time when Logres was only myself and one man and two boys, and one of those was a churl. Yet we conquered.”
“It could not be done now. They have an engine called the Press whereby the people are deceived. We should die without even being heard of.”
“But what of the true clerks? Is there no help in them? It cannot be that all your priests and bishops are corrupted.”
“The Faith itself is torn in pieces since your day and speaks with a divided voice. Even if it were made whole, the Christians are but a tenth part of the people. There is no help there.”
“Then let us seek help from over sea. Is there no Christian prince in Neustria or Ireland or Benwick who would come in and cleanse Britain if he were called?”
“There is no Christian prince left. These other countries are even as Britain, or else sunk deeper still in the disease.”
“Then we must go higher. We must go to him whose office it is to put down tyrants and give life to dying kingdoms. We must call on the Emperor.”
“There is no Emperor.”
“No Emperor . . .” began Merlin, and then his voice died away. He sat still for some minutes wrestling with a world which he had never envisaged.
Here, as I think Christopher Derrick pointed out, the story suffers from Lewis’s own lack of Catholic faith.  The real Merlinus Ambrosius would doubtless have also asked about the Pope of Old Rome. And he would have wanted to know more about the ‘pieces’ into which the Faith had supposedly been torn, to discover whether he was sitting with Catholics or heretics (Warren Carroll pointed out in an unforgettable passage in his History of Christendom that in the later 5th century, all the kings in Europe were either pagans, heretics or schismatics, with the single exception of Arthur, who alone stood with the pope.)
This flaw apart, the conversation is excellently well done:
Presently he said, “A thought comes into my mind and I do not know whether it is good or evil. But because I am the High Council of Logres I will not hide it from you. This is a cold age in which I have awaked. If all this west part of the world is apostate, might it not be lawful, in our great need, to look further . . . beyond Christendom? Should we not find some even among the heathen who are not wholly corrupt? There were tales in my day of some such: men who knew not the articles of our most holy Faith but who worshipped God as they could and  acknowledged the Law of Nature. Sir, I believe it would be lawful to seek help even there – beyond Byzantium. It was rumoured also that there was knowledge in those lands – an Eastern circle and wisdom that came West from Numinor. I know not where – Babylon, Arabia, or Cathay. You said your ships had sailed all round the earth, above and beneath.”
Ransom shook his head. “You do not understand,” he said. “The poison was brewed in these West lands but it has spat itself everywhere by now. However far you went you would find the machines, the crowded cities, the empty thrones, the false writings, the barren beds: men maddened with false promises and soured with true miseries, worshipping the iron works of their own hands, cut off from Earth their mother and from the Father in Heaven. You might go East so far that East became West and you returned to Britain across the great Ocean, but even so you would not have come out anywhere into the light. The shadow of one dark wing is over all Tellus.”
In other words: just as it is a good discpline for the mind to translate one’s words into a foreign language, especially if it be very foreign, such as Latin or (I suppose) Chinese, since that forces one to think more clearly about what one really means, so it is a good discipline for the soul to explain one’s own times to someone from ages past, and so begin to see them as they really are.
* I had to look up tire-woman.  It means lady’s maid, tire being short for attire.