Is there any critic more thorough than Helen Vendler? Her relentless, painstakingly evidenced argumentation may be found not only in her more sustained, more specialized efforts — from “On Extended Wings” (1969), her first study of Wallace Stevens, to “Invisible Listeners: Lyric Intimacy in Herbert, Whitman, and Ashbery” (2005) — but also in her criticism in the New Republic, the New York Review of Books, and elsewhere. Ms. Vendler’s academic background, in other words, is always visible — as is her devotion to and love of poetry in English — in whatever she writes. Her carefulness, her attention to minutiae, is a rare quality, particularly when set against the current mores of poetry criticism, which, for all its highly technical vocabulary, has been for many years an enterprise largely impressionistic.

Ms. Vendler laudably refuses to discard the monumental figures of English poetry — and, more important, refuses to reshape them, as Christian historians did to the intractable titans of the Hebrew Bible, solely as augurs and forerunners of our current condition. Any serious reader of English poetry should be delighted that, in “Our Secret Discipline” (Belknap Press, 428 pages, $35), she has turned her attention to the question of form in W.B. Yeats’s poetry. (The poet, or rather his later plays, was the subject of Ms. Vendler’s dissertation.) Yeats is a particularly thorny figure for well-meaning rehabilitators: His eccentric political and religious beliefs, never very clearly separated, and the powerful role of premodern myths and theological systems in his lexicon of metaphor make him a difficult creature to claim as an ancestor of contemporary poetry.