Some of the Chicago School's essays on poetry can seem dry and abstract. They focus on method, on the criticism of criticism; there's a high degree of theoretical abstraction. But it's worth the effort to work through them. Elder Olson's essay (found in Critics & Criticism), "William Empson, contemporary criticism, and poetic diction", is absolute gold.
American poetics of the latter part of the 20th century was all about language, vocabulary, ambiguity, diction, spearheaded by the "alienation effect" of the Language poets' critique of all the other styles then current. In this the LPs were in line with the New Critics.
The popular image of the NCs is that of old white academic fuddy-duddies, the establishment against which the Projectivists, Confessionals, New Americans, Beats, Afro-Americanists, Deep Imagists - all the movements of the 50s & 60s - were in revolt. But the NCs were actually radical innovators in their own right. It's the Chicago School which represents something like a true return to classical poetics - they are the real old fuddy-duddies. & they are so old-fashioned that now, in 2008, their ideas sound, at least to this poet, very radical indeed. I say that anyone who reads & digests Olson's piece on Empson will discover a whole new way of thinking about and responding to poems. Notions of poetic language, and the meaning of "meaning" in poetry, will be sharply revised.
Olson was interested in the poem, not as language, but as ACTION. In this he curiously chimes with his near contemporary, that other Olson! Charles Olson, the great scourge of Western philosophy, would be mortified to find how Aristotelian he seems, through the lens of Elder Olson. Charles O. also thinks of the poem as ACTION - but he envelopes his sense of the poetic act in the feathery mantle of the pompous Magus-Poet. A kind of suprematism - the Act of the Breath of the Line makes a Micro-Cosmos... the Instauration of the Local Epic World-Body of Bodies in Action... thus Charles went to the extremes at either end - the limits being the (Poundian) beak of his Ego, and Epic. Elder, on the other hand, understood beauty as an Aristotelian mean between excess and deficiency. He was interested in the action of the poem as mimesis or imitation. (& I don't mean to make too much fun of Charles O., though he certainly deserves it - would be more interested in exploring ways Charles actually fulfilled Elder's conception of poetry - & challenged the NCs - than in contrasting the two of them at Charles's expense. Maybe Charles is to Elder somewhat as Whitman was to Emerson!)
How is it these Chicago critics never had much influence in poetryland? Perhaps they fell through the cracks between the instauration of the New Criticism in academia, which I guess ran through the 50s (Understanding Poetry was their big textbook - which I need to take another look at), and the rise of the Confessionals & New Americans et al. The "mainstream" slice-of-life poetries of the 60s and 70s were mocked and derided by Langpos & NY School alike, for lacking theory and self-reflexive irony; they had a master critical school just sitting there on the shelf, which might have been applied in their defense.
But everything you need, to put away for good most of the language-oriented poetries of the 80s & 90s, is right there in Elder Olson. Read it and leap.
(It makes you wonder what they've been teaching in MFA programs, and what the public pontificators on poetry over the last 3 decades have been doing. I never heard about this in my English or writing classes, back in the day. They all get an "F" for ignoring the theoretical work of the Chicago School, as it applies to poetry.)