The strengths and limitations of poet-critics, as a class, seem to come from intensity of focus: They need to think about writing, about poetic composition. And any insight or idea in their criticism grows somehow from the complex, subterranean roots of concern with composition, and with the circumstances of composition. These collected lectures and reviews ["Preoccupations"] by the gifted Irish poet Seamus Heaney often explore those roots in exciting ways, dealing intimately with composition as an act of mind more profound than mere rhetoric, and showing how the circumstances of composition extend to the most urgent, painful historical questions.

The moments of such penetration come primarily, I find, when Mr. Heaney meditates on his personal and national past—Irish speech, landscape, history, poetry, and hereditary blood-struggles—touching and testing the links between them. The most moving piece in the book, the lecture "Feeling Into Words," confirms the idea...