“As the ramp went down we were getting direct fire right into our craft,” wrote a soldier in the 116th on the western part of Omaha. “My three squad leaders in front and others were hit. Some men climbed over the side. Two sailors got hit. I got off in water only ankle deep. I tried to crawl but the water suddenly was up to my hips. I crawled to hide behind the steel beach obstacle. Bullets hit off of it and through my pack missing me. Others hit more of my men.”

Renowned military historian Antony Beevor, author of the bestselling Stalingrad and The Fall of Berlin 1945, here uses the words of a U.S. infantryman to evoke the famous June 6, 1944 landing at Omaha Beach, part of the massive Operation Overlord, when the Allies invaded Nazi-occupied France and began pushing Hitler’s armies eastward into the German fatherland. Beevor’s impressively researched and accessibly narrated account of the turning point of World War II begins a few days before the invasion, as Supreme Allied Commander Dwight Eisenhower prays for good weather, and ends on August 25th, when Allied troops triumphantly liberate Paris. The focus swivels with meticulous precision to illuminate the military, political, and personal dynamics on all sides, offering the perspectives of the American, British, Canadian, French, and German militaries.

Though the successful invasion would be seen for decades as a symbol for the spirit of cooperation between the Allies, Beevor opens D-Day with a close look at the strong strategic differences and seemingly intractable personality conflicts that threatened the cohesiveness of the operation. In the days before the massive June 6th landing, General Eisenhower was a wreck, concerned about the weather and final preparations while trying to keep his fractious Allies together. “Although outwardly relaxed,” Beevor writes of Ike, “with his famous open smile for everyone whatever their rank, he was smoking up to four packs of Camel cigarettes a day. He would light a cigarette, leave it smoldering in an ashtray, jump up, walk around and light another one. His nerves were not helped by constant cups of coffee.” Ike had ample reason for nervousness.

Field Marshall Bernard Montgomery, the legendarily pompous and egocentric British commander, tolerated his boss Eisenhower as a person but had absolutely no respect for him as a military leader. Beevor cites Monty’s dismissal of Ike: “Nice chap, no soldier.” Eisenhower also had the almost impossible task of keeping France’s General Charles DeGaulle — a man who was perhaps even more vainglorious than Montgomery — happy. When, for example, Ike saw no military rationale for occupying Paris in August 1944 and preferred bypassing it so as to continue pushing the Nazi armies eastward, the high-maintenance DeGaulle had a fit and threatened to divide the Allied armies by ordering his French troops to occupy Paris. DeGaulle got his way.

Even within American ranks, Eisenhower had untamed personalities to manage, most famously General George S. Patton. Although Patton hated Montgomery’s guts (they were bitter rivals for military glory), he shared Monty’s low opinion of Ike as a military man. Patton, Beevor tells us, considered his commander a mere politician who wanted popularity. Patton rejected Ike’s democratic style of leadership: “A commander cannot command and be on the same level [as his troops]…. I try to arouse fighting emotion — he tries for votes.” But despite the criticism directed Ike’s way from many sources, Beevor portrays him as a selfless leader whose diplomatic skills and singular ability to collaborate kept the Allies working — and winning — together.

If Beevor brilliantly showcases the fractious relations among the leaders on the Allied side, he doesn’t fail to show how similar disarray undermined the Germans’ efforts. Perhaps most significant was Hitler’s insistence on his own judgment over those of his commanders. In the days before June 6th, Hitler believed an invasion would come, but he refused to be convinced that it would come in Normandy. Beevor recounts the very successful Allied disinformation campaign that fed into Hitler’s mistaken preconceptions — so effective that when the Allied invasion hit the Normandy beaches, Hitler considered it a diversion. His fateful delays of reinforcements allowed the Allies to establish the crucial beachhead.

Hitler’s bad relationship with his generals made disagreements on the Allied side seem like momentary squabbles. The German commander in charge of defending Normandy, the famed Field Marshal Erwin Rommel, disagreed completely with Hitler on how the German army should be deployed. Hitler wanted his troops to give no ground, to fight to the death for every inch. Rommel, on the other hand, wanted a more flexible defense that would mean pulling back, concentrating his forces, and pounding the Allies with a massive counterattack. Hitler won this battle, but Rommel remained furious.

As Beevor explains, “Hitler’s blind belief was that his new Vengeance weapon [the V-1 missile] would knock Britain out of the war.” But Hitler’s fantasies never materialized — though horribly damaging to their civilian targets, the rockets were unable to alter the fundamental military equation. Hitler “was out of touch with reality,” writes Beevor, “and when his dreams failed to materialize, he looked for scapegoats.” In the ongoing war between Hitler and his generals, the Führer executed some for not following his “no surrender” policy — and a few responded by attempting to assassinate their paranoid leader.

D-Day’s account of the June 6th amphibious landing, its chaos and carnage at beaches like Omaha and Sword — as some 175,000 men arrived in waves while German defenders aimed artillery and machine-gun fire their way — and the grind-it-out fighting in the weeks after, is military history at its visceral best. Beevor’s understanding of the strategic situation on both sides, and the personalities and leadership, gives his readers a solid sense of what’s at stake in each battle. But the book also makes plenty of room for the moment-by-moment struggles of enlisted men facing possible death and certain exhaustion, and working tirelessly to complete the job — often quoted from their own letters home and interviews that render their point of view as close to nakedly as one can get.

The war’s turning point, Beevor makes clear, was nothing as simple or swift as a day’s taking of beachheads. The reality was more brutal and exhausting. Normandy would end up as a battle of attrition favoring the Allies. The Germans were fighting on two fronts, the Eastern (against Stalin’s armies) and Western (in Normandy) and were being slowly bled dry. Beevor gives us a typical example from the German side: “Army Group B reported that since the [June 6th] invasion they had suffered 151,487 casualties, dead, wounded and missing. They had received fewer than 20,000 replacements.” The total cost of the Normandy invasion and its aftermath on the German side was 240,000 casualties and another 200,000 taken prisoner. The Allied losses were similar, but they could replace their losses, while each day of defending the conquered ground sapped Germany’s ability to do so.

Beevor ends his comprehensive account with French troops entering Paris on August 25th. It is to General Eisenhower’s credit that he allowed the French armies to claim the invasion as a French victory and to promote the illusion that “[t]he shame of 1940 [surrender to Germany] and the Occupation” had never happened. By compromising here, allowing DeGaulle and France to believe that they had won, Eisenhower ensured that the Allies would stay together during the final push eastward into Germany. Brilliant fighting men like Patton and Montgomery were against allowing the French to engage in triumphalist fantasies, but Eisenhower had a war to win, and he proved, contra Montgomery, that he was the supreme soldier — for he would sacrifice almost anything to beat Hitler. The war would be over within months.