Louis Zukofsky, who died in 1978 at the age of seventy-four largely unknown to the majority of critics and readers of American poetry, was one of the century's most fascinating and accomplished poets. Physically and personally unprepossessing--an apparitionally thin, chain-smoking hypochondriac, Zukofksky in his later years saw visitors only with extreme reluctance and would refuse to speak above a whisper when he thought he might be overheard--this child of non-English-speaking immigrants came to master the English language and to create a large corpus of writings of unsurpassed aural delicacy, emotional subtlety, and intellectual rigor.

In or about 1950 Zukofsky in "A"-12 defined his poetry in mathematical terms: "An integral / Lower limit speech / Upper limit music." While Zukofsky's verse spends more time in the upper than in the lower reaches of this equation, proposing an order of pleasure that is more dependent on sound than meaning, his poetry is never...