IN SUCH EARLIER works as The Performing Self, a brilliant study of American culture, Richard Poirier has proved himself one of our most perceptive critics.Robert Frost: The Work of Knowing is in many ways an equally perceptive, thoughtful and rewarding work of literary criticism, certain to maintain Poirier's reputation, yet it remains a mixed bag of delights and disappointments.

Poirier easily dismisses certain common notions about Frost; he takes exception both with Lionel Trilling's characterization of Frost as "a terrifying poet" and with the more popular idea that Frost is our easiest, more accessible poet, content to uphold without question the simple joys of home and nature. He maintains, however, that the popular notions about Frost - while limited and unsatisfactory because they do not give the poet credit for what Poirier sees as his "technical genius" and "originality of mind" - are nevertheless rooted in a certain truth.Far from attempting to challenge "old verities and pieties," as Trilling suggested, Frost was, according to Poirier, trying "to reinstate them." Yet, having "reinstated" conventional beliefs and sentiments, Frost was often forced by his engrained and tough-minded skepticism of ultimate meanings to twist those "old verities" askew in the end, to qualify them by withdrawing. the promised comfort. Frost's poetry is at its best, Poirier says, "when it makes of the 'obvious' something problematic, or when it lets us discover, by casual inflections or hesitations of movement, that the 'obvious' by nature is problematic."

And Poirier is at his best when he is showing us how Frost achieved this, the navigation of his mind as he tried too little and too much." Poirier demonstrates convincingly that a central situation in the poems is the journey outward towards a dangerous destination, a kind of wandering which he calls "extravagance" (or sometimes, coyly, "extra-vagance"), from which the wanderer always returns "home with or without the spoils." Much of Frost's best poetry, Poirier believes, "emerged from a central nervous tension about 'home' and 'extravagance.'"Poirier maintains, in fact, that the tension is also between poetic form or "decorum" ("home") and the need for going beyond it, for a kind of metaphoric "extravagance," veering off into the "sublime."

Poirier's most rewarding discussions are perhaps those of Frost's dramatic poems, particularly those in which "'home' is at its worst," the dramatic poems about women in the country. Frost had an extraordinary understanding of "the plight of women who have nothing but a home to keep," and in such poems as the powerful "Home Burial," he showed how "the frustrations of imagination" might result in the "distorted forms of obsession, lies, or madness." In "Home Burial," the "home" itself becomes the source of fears from which it is supposed to serve as shelter. Also interesting are Poirier's interpretations of such poems about the "natural world" as "Spring Pools" or "The Most of IT," poems in which that world takes on a larger import. In "Spring Pools," for example, Frost begins with an Emersonian notion of oneness and unity, only to draw back in the last lines to a vision of "apocalyptic obliteration."

Robert Frost is a difficult book because it presupposes an extensive knowledge not only of Frost but of a whole range of modern literature, particularly Eliot, Joyce and Stevens. One would assume, of course, that it is not a blook for the casual reader. But even the reader who comes to it armed with the proper background may have his difficulties. I think this is because Poirier may have read too much "fashionable" contemporary criticism. Too much criticism these days is written in a style that seems unnecessarily dense, showing a penchant, for example, for such indulgences as "veri-fication." One feels that there must be a secret code needed to decipher the message, and Poirier sometimes falls into the trap. Contemporary critics also have a fondness for talking about the "visionary" and the "sublime" in poetry and for reading every poem as meditation on the nature of poetry itself. When Poirier tries to do this with Frost he seems to be stretching the point a bit; his own discussions of Frost as a tough-minded, acutely observant skeptic make it difficult to imagine. Nevertheless, those interested in Frost will find Poirier enlightening, well worth the difficulties.