Going After Cacciato is, without reservation, one of the most challenging and powerful novels to find its way into print in some time.

O'Brien's infantry experience in Vietnam seems to have determined the shape and content of his literary career thus far. He wrote an undistinguished first novel, Northern Lights, and an excellent work of nonfiction, If I Die in a Combat Zone. With this third book he has accomplished something of a miracle. By using all the authentic and bloody detail that he knows so well from the war he survived, he has created a narrative that borders on myth and theology, psychology and epic, a picaresque parable of the imagination.

I have tried to find a novel to compare it to, to convey to the reader of the review not so much the story as the quality of the work. The closest (in one sense) I...