This collection of essays was published in 1931. It is available as a separate publication, and also included in Volume 1 of the LoA edition of E.Wilson, who was one of America's most important literary critics in the 30s to 50s. I knew him initially mainly due to his relationship with Nabokov, which is summarized in an entertaining letter collection: Dear Bunny, Dear Volodya.
In Axel's Castle, Wilson tells us the history of fiction and poetry since 1870 with a focus on 'schools'. In broad strokes: Romanticism had been born as a rebellion of the individual and disorder against the orderliness of Neo-classicism. With the growth of science during the 19th, the reaction against the romantic school was Naturalism, which in turn provoked Symbolism as the extrapolation of the romantic rebellion. EW claims that all relevant literature up to the time of his publication could be put in either the Symbolist drawer, or the Naturalist one, or they were syntheses of both.
That may all very well be the case, but I find it rather uninteresting. What is interesting is the individual writer, not any school that brought him/her forth.
The essays cover specifically Yeats, Valery, Eliot, Proust, Joyce, Gertrude Stein, Villiers de L'Isle Adam and Rimbaud. Not to forget the road from Stein to Dada via plain nonsense.
I think that no writer who needs a label for his characterization has been really great. The most interesting essays in the collection are therefore those on Proust and Joyce. Unfortunately, EW tried to squeeze them into his bed of Procrustes, but that notwithstanding, the discussions of La Recherche and of Ulysses are making this volume worth while. They add to our understanding and are helpful if you have a basic knowledge of the two monster books already. If not, they give you a good starting point.
And then, EW tries to tell us that Proust reflects the new theories just developed by Einstein & Co. That the changing light, in which the protagonists in the Recherche appear over time, is exemplifying for us the theory of relativity. What crap.