Because of its stunning, violent imagery and terrifying ritualistic language, “The Second Coming” is one of Yeats’s most famous and most anthologized poems; it is also one of the most thematically obscure and difficult to understand. (It is safe to say that very few people who love this poem could paraphrase its meaning to satisfaction.) Structurally, the poem is quite simple—the first stanza describes the conditions present in the world (things falling apart, anarchy, etc.), and the second surmises from those conditions that a monstrous Second Coming is about to take place, not of the Jesus we first knew, but of a new messiah, a “rough beast,” the slouching sphinx rousing itself in the desert and lumbering toward Bethlehem. This brief exposition, though intriguingly blasphemous, is not terribly complicated; but the question of what it should signify to a reader is another story entirely.

Yeats spent years crafting an elaborate, mystical theory of the universe that he described in his book A Vision. This theory issued in part from Yeats’s lifelong fascination with the occult and mystical, and in part from the sense of responsibility Yeats felt to order his experience within a structured belief system. The system is extremely complicated and not of any lasting importance—except for the effect that it had on his poetry, which is of extraordinary lasting importance. The theory of history Yeats articulated in A Vision centers on a diagram made of two conical spirals, one inside the other, so that the widest part of one of the spirals rings around the narrowest part of the other spiral, and vice versa. Yeats believed that this image (he called the spirals “gyres”) captured the contrary motions inherent within the historical process, and he divided each gyre into specific regions that represented particular kinds of historical periods (and could also represent the psychological phases of an individual’s development).

“The Second Coming” was intended...