David Jones, the author of "In Parenthesis," the most monumental work of poetic genius to come out of World War I, and of the greatly admired "Anathemata," left behind a mass of papers when he died in 1974. Collected here under the title "The Dying Gaul," they supplement the essays he published during his lifetime, "Epoch and Artist." His essays, like his poems and paintings, are the works of a visionary who seemed so rooted in his own life—separate from other lives yet inseparable from his work—that he did not belong to the literary world of his time….

If Jones's geographical habitat is Celtic, his historical habitat is Wales before the Christian era and some centuries after it, the times of early Christianity. His connection with the past is neither nostalgic nor literary and antiquarian. It is archeological—established through contact with things….

The very special charm...