To enjoy the book, you have to be willing to ignore a lot of tendentious argumentation, to say nothing of Winters's sharp personality. He despises relativism, and takes a firm, self-congratulatory stand on the side of Absolute Truth. Here is a passage from his essay on Henry Adams:
"Adams quotes Poincare as saying that it is meaningless to ask whether Euclidean geometry is true, but that it will remain more convenient than its rivals. I am no mathematician and can only guess what this means; but I surmise it means that a bridge built by Euclidean geometry may conceivably stand, whereas one built by a rival system will certainly fall. If this is true, I should be willing to accept the fact as perhaps a Divine Revelation regarding the nature of the physical universe and as a strong recommendation for the study of Euclidean geometry."
You may say that Winters is speaking with his tongue in his cheek but I don't see in the book anything more solid to back up his Realism than the Pragmatism of this passage, a Pragmatism that would give him the vapors if he found it in some passage by Emerson. On the other hand, his constant denunciations of determinism and hedonism aren't entirely useless, and occasionally, as in the essay on Wallace Stevens, are even used to good effect. Mostly I find them tiresome, ascribing far more psychological and historical weight to abstruse philosophical issues than my materialist mind is comfortable with.
Leaving philosophy behind, he's an excellent literary critic: capable, perceptive, immune to any cant but his own. Here are worthwhile essays on poetic meter, Dickinson's excellent, too-precious, sickly poems, Henry Adams' bizarre personality and magisterial history of the Jefferson administration, Eliot's cheap, groundless conservatism, etc. And in the end I agree with him that the mimetic fallacy has done a fair amount of damage, although as soon as I admit it he starts fulminating against Calvinism or something.
He says rightly that Wallace Stevens was our best poet from the last century, and then wrongly that Sunday Morning was his best poem. There's something pompous and doctrinaire about the poem that's always set my teeth on edge, despite the language, and I see the same in Winters. Certainly one of the best American literary critics, and maybe the most under-appreciated.