COLLECTED POEMS OF WILLIAM EMPSON (113 pp.)Harcourt, Brace ($2.50).
There is a kind of "intellectual" poetry that the everyday reader is right in never bothering his head about; if he did, he would find it about as unrewarding after study as before. But there is another kind that, like differential calculus and other forms of honest brainwork, has a permanent beauty worth a closer look. Of all living writers, none has done more as a critic to keep this distinction clear or more as a poet to illustrate it than bush-bearded, 42-year-old Englishman William Empson, who now lives by choice in Peiping....