Over the years, Jacques Barzun, University Professor of History at Columbia, has had to help many students recast their work into readable prose. This primer in rhetoric is aimed at the same audience, i.e., those tyros, chiefly academics, who write in hope of publication. Barzun covers the standard topics--diction, sentence structure, tone, precision of meaning, and composition--and adds a salutary chapter on the inevitable revisions. Barzun includes many examples of literary infelicity which the reader is supposed to rework (though his failure to provide ""solutions"" or hints tends to undermine their usefulness) and gives several examples of what he considers to be good prose. Most of them are In fact little known and quite striking. As a text, however, or even as a desk-top standby, this has only limited value: Barzun's informal organization and conversational tone preclude easy reference to comments on any specific problem of style or word usage. His own prose is generally competent, often urbane. As useful as those now out-of-fashion copybook exercises.