Ambrose, who signed on as historical consultant to the film, has dedicated much of his life to illuminating the truth about D-Day and the Normandy campaign of 1944. He is the author of the best-selling books D-Day, June 6, 1944 and Citizen Soldiers; he is also the founder of the Eisenhower Center for American Studies in New Orleans, where more than 1,000 oral histories of World War II veterans have been collected.

In Saving Private Ryan, Captain John Miller (Tom Hanks) survives the American landing at Omaha Beach in World War II, but then he’s given a new mission: to find and extract Private James Ryan (Matt Damon), the youngest of four brothers, the other three of whom have been killed in action elsewhere in the war.

The plot is inspired in part by the true story of Fritz Niland, one of four brothers from New York state who saw action during the war. Two Niland brothers were killed on D-Day, while another went missing in action in Burma and was presumed dead, although he actually survived. Fritz was located in Normandy by an Army chaplain, Reverend Francis Sampson, and taken out of the combat zone.

"A film on World War II--or any historical subject--has a responsibility to be honest, but with the scope to say ‘what if?’" says Ambrose.   "What if Father Sampson hadn’t found Niland right away? What would the Army have done?"

Captain Miller’s search for Private Ryan becomes a lens through which Spielberg and screenwriter Robert Rodat examine the American experience at Normandy--particularly the bitter inland battles that followed the June 6 landing. "D-Day has all the drama to it," says Ambrose, "but there was tough fighting to follow."

According to Ambrose, there were many real-life officers like the fictional Captain Miller, such as Joe Dawson and John Spalding, commanders who were among the first up the bluff at Omaha.  "So when Miller decided to go for that pillbox, I thought, yes, that’s what they would have done, that’s right," Ambrose says.

Attacking heavily fortified positions, the Americans suffered about 2,400 casualties at Omaha on June 6, and Spielberg is unsparing in his depiction of the destruction on the battlefield.   The honest treatment of death on the battlefield in Saving Private Ryan is radically different from those found in other films in the World War II genre.

In earlier films, such as Darryl Zanuck’s 1962 D-Day epic The Longest Day, soldiers die quick, romantic, noble deaths, never knowing what hit them. "That happens in about one percent of the cases," says Ambrose. "Ninety-nine percent of the time, they know damn well what hit them. They’re 18 years old, they’re terrified, and they’re not at peace with their maker or anything else like it."   Spielberg’s Omaha Beach is deafening and chaotic, in sharp contrast to the battlefields of an earlier generation of World War II films. "In those films, without exception, the battles are too clean, too neat, too surgical, too short, too good to be true," says Ambrose.

Long, sweeping aerial views of the invasion are replaced by tight shots and quick cuts as Spielberg and director of photography Janusz Kaminski seek to personalize the battle and represent the perspective of the infantry.   One notable shot is from the viewpoint of a German soldier in a casemate; his machine gun is trained on an American landing craft, and the troops are killed before they can leave their boat. This was a common occurrence for the first wave of American infantry at Omaha, particularly at the Dog Green sector, where Miller’s company lands.

Farther inland, the troops witness the disarray of the paratroopers of the 82nd and 101st airborne divisions, whose off-target drops on the night of June 5-6 threw much of the first week of the invasion into confusion. A haggard CG-4 pilot tells a harrowing story of crashing his overloaded glider. Sporadic firefights against "targets of opportunity"--the squad attacks a radar site and engages in a brief skirmish with a German squad on a half-track--were characteristic of the inland fighting at Normandy. The weaponry depicted in the film--Sherman tanks, DUKWs, bazookas, Panzerschrecks--is historically accurate.

"The film illuminates the truth of how tough these troops were, how gung ho they were, how piqued up they were," says Ambrose. He notes that on the eve of the invasion, when the forces were assembling in Portsmouth Harbour on the southern coast of England, army rangers were still training--doing pushups and climbing cables on the ships.

Ambrose is listed as historical consultant to the film, although he became directly involved with the movie only after it was completed. The screenplay is heavily influenced by Ambrose’s books on the Normandy invasion; the story of Fritz Niland is told in Ambrose’s 1992 Band of Brothers.

The overriding theme of Ambrose's writing on the war is that, contrary to Hitler's assumptions, democracies can indeed produce outstanding soldiers.  The bravery shown by American troops in taking the German casemate at Omaha Beach is consistent with Ambrose’s theme. "If these guys had cowered behind the seawall and said ‘I’m staying here, I’m not going to take any risk,’ the landing would have failed at Omaha Beach," says Ambrose. Failure at Omaha Beach would have been catastrophic for the invasion, he notes, leaving a gap between the British and Canadian beaches that could have been exploited by German Field Marshal Erwin Rommel’s heavy armour.