D-DAY: JUNE 6, 1944, The Climactic Battle of World War II, by Stephen A. Ambrose, Simon and Schuster, 655 pages, $30.

Military history tries to make sense of the inherent confusion of war, giving the reader a sense of the importance of a specific moment in a battle even if the participants themselves are unaware of it. As a biographer of Dwight D. Eisenhower and the author of previous works on one D-Day mission, “Pegasus Bridge,” and a history of the 101st Airborne Division, historian Stephen Ambrose has a broad background which helped him sort out the complexity and disorder of his latest subject.

The flood of recent television specials and other D-Day related books compete with Ambrose’s extensive work and might intimidate someone with just a passing fancy in the invasion’s 50th anniversary. The book becomes compelling by a clear description and analysis of the day’s events and by putting it into the context of World War II itself. Ambrose knows many readers are probably familiar with the general facts about the invasion itself, but makes it fresh by a brief outline of the war to that point and the departure in the course of the war that D-Day marked.

The production of war materiel, the reaction of the home fronts during D-Day, the massing of Allied forces in Britain and the deception over where the invasion of Europe might happen all have their place in the book. Perhaps the most overdone cliche in military history is how a certain person, event or weapon “won the war for us.” Eisenhower himself is quoted in this book as saying that the creator of the amphibious Higgins boat, Andrew Jackson Higgins, helped win World War II. However, what emerges from the book more than anything else is the connection between the different factories, leaders and armed forces. Ambrose writes that the invasion’s success rested with a relatively small group of men from different nations, yet always mentions the plentiful supplies and transportation that got the men of D-Day to the start of their respective missions.

Thanks to the interviews from the Eisenhower Center and other sources such as the American Military Institute and the Imperial War Museum, people stand out from the ranks of thousands, people like Pvt. James Eads of the 82nd Airborne, whose landing in Normandy was cushioned when he dropped onto a manure pile. Hungry British commandos who devoured strawberries before liberating more of the countryside faced a French farmer who told them the Germans had been there for four years and never ate one.

Ambrose tells of men whose bravery equaled a John Wayne movie and those who cowered in fear when their time came to act. World War II is often remembered as “the good war,” but the pain of loss appears again and again throughout the book. Before the invasion soldiers often played softball for recreation and exercised while cooped up in their camps, according to Ambrose. “There were barrels full of gloves and balls and constant games of catch,” he wrote. “A number of men recalled that these were the last games of catch they ever played because of wounds they received or arms lost during the ensuing campaign.”

Avenging loss became another factor for some soldiers. Young European Jews changed their last names to English ones before D-Day so they might avoid German retribution if captured in the middle of their own personal attempt at liberation. Free French and Polish soldiers made up the ranks of others who thought of family and home along with the military objectives.

Even though racism was at the heart of Nazi philosophy, Ambrose notes that the American military had its own prejudices when it came to black soldiers, forcing many to work in service or supply jobs and face segregated pubs in nonsegregated Great Britain. Only later — during the Battle of the Bulge when the Allies were hard pressed for soldiers — would blacks have the chance to demonstrate their own bravery, according to Ambrose.

The lists of definitions of military abbreviations like DUKW (“duck,” a 2 1/2-ton amphibious truck) and how many men make up a squad and platoon make reading easier for people without extensive knowledge of military affairs. He writes in the introduction that the book is meant to be a “love song to democracy,” about how people from democratic nations defeated a mighty totalitarian nation. Americans today might remember World War II as one in which the United States was unstoppable after Pearl Harbor, not as Ambrose more accurately describes it, a formerly isolationist country embarking on an unprecedented invasion of size and scope in 1944.

The men of D-Day did not grow into a proud military tradition, but a society doubtful of war. “The literature they read as youngsters was anti-war, cynical, portraying patriots as suckers, slackers as heroes. None of them wanted to be part of another war,” Ambrose wrote.

Although Ambrose tries to give a face to some of the individual men of the invasion, the sheer scope of D-Day dominates the book: the biggest memory for many is the size of the invasion itself, a previously empty ocean blackened with ships from the United States to Poland. An armada of countries which had once desperately wanted to avoid war took on huge risks not for their own interests or glory, but to fight for their own ideas, despite the high costs.

Michael Reagan lives in Portland.