The author immediately makes good, tightening his focus on Hitler’s most celebrated general:

In the ground-floor room he used as an office, Rommel was alone. He sat behind a massive Renaissance desk, working by the light of a single desk lamp. The room was large and high-ceilinged. Along one wall stretched a faded Gobelin tapestry. On another the haughty face of Duke Francois de la Rochefoucauld—a seventeenth-century writer of maxims and an ancestor of the present Duke—looked down out of a heavy gold frame. There were a few chairs casually placed on the highly polished parquet floor and thick draperies at the windows, but little else.

Nothing slows the eye’s journey across the page; the author feels no compulsion to call out, “Look over here, it’s me!” And this makes it easy to miss what is so striking about this otherwise simple passage: the efficient accumulation of fact.

We learn that Rommel was a) alone, b) seated at a desk that was c) massive and d) Renaissance and fitted with a single lamp, and that he worked under the gaze of e) Duke Francois de la Rochefoucauld whose face was f) haughty and whose portrait was framed in g) gold. And then, quite subtly, Ryan offers a quick peek at his character: “In particular, there was nothing of Rommel in this room but himself.” Not a photograph of his wife (Lucie-Maria) or son (Manfred, age fifteen) or mementos of his great victories in North Africa, such as the field marshal’s baton Hitler had presented him (eighteen inches, three pounds, gold, red velvet covered with gold eagles and black swastikas) because such extravagance, Ryan writes, was alien to Rommel, a man who “cared so little for food that he sometimes forgot to eat.”

Rommel did not know when the Allies were coming nor where they would land. But, Ryan tells us, his defenses were stretched thin and he decided to return to Germany and plead for more materiel from Hitler. He would stop at home along the way to present a pair of shoes (gray suede, size five and a half) to his wife on her birthday, June 6.

Size five and a half? How did he get that?

Cornelius Ryan was at Normandy twice on D-Day, the first time on a bomber flying over the beaches, the second time on a patrol boat that took him back after he landed in England. He had turned twenty-four the day before. He had been working as a war correspondent for London’s The Daily Telegraph since 1943, having come to London from Dublin in 1940, and to journalism a year later at Reuters, after attending a school where he studied violin. He covered the air war over Germany—perilous work—as well as Patton’s Third Army, then reported from the Pacific.

In 1947, Ryan moved to the United States, where he became a naturalized citizen and, eventually, a writer for Time, Newsweek, and, until its demise in 1956, Collier’s. By then, he had written four books, including two about Douglas MacArthur, and another, One Minute to Ditch, about an airliner’s ocean landing. He also published a good many magazine stories that, taken together, reflected less a budding literary career—“I Rode in the World’s Fastest Sub”—than the workmanlike yield of a man who knew how to churn out copy.

But one story did suggest that, given the chance to pursue the best material, Ryan could produce memorable work. In 1956, the liner Andrea Doria collided with a Swedish ship off the coast of Nantucket and sank. Ryan set about reconstructing the collision, the rescue of all but forty-six of the ship’s 1,706 passengers, and most memorably, the drama of a husband and wife who had switched beds the night before, only to be woken when a beam split their cabin—separating them, as it turns out, forever. The writing was at times overdone. But the reporting, which included the surviving husband’s moment-by-moment account of his wife’s demise, was a harbinger of the big projects to come.

Ryan had initially proposed a D-Day book about only the first two or three hours of the invasion. But then he began to report, and his ads (“Personal: Were You There on 6 June 1944?”) yielded thousands of responses. He followed up with a three-page questionnaire that could serve as a primer for reconstructing a narrative: Where did you land and at what time? What was the trip like during the crossing? Do you remember, for example, any conversations you had or how you passed the time? Were you wounded? Do you remember what it was like—that is, do you remember whether you felt any pain or were you so surprised that you felt nothing?

Michael Shapiro is a contributing editor to CJR and teaches at Columbia's Graduate School of Journalism. His most recent book is Bottom of the Ninth: Branch Rickey, Casey Stengel, and the Daring Scheme to Save Baseball From Itself.