The Longest Day is a 1962 American epic historical war drama film based on Cornelius Ryan's 1959 non-fiction book of the same name[3] about the D-Day landings in Normandy on June 6, 1944.

The film features a large international ensemble cast that includes John Wayne, Kenneth More, Richard Todd, Robert Mitchum, Richard Burton, Steve Forrest, Sean Connery, Henry Fonda, Red Buttons, Peter Lawford, Eddie Albert, Jeffrey Hunter, Stuart Whitman, Tom Tryon, Rod Steiger, Leo Genn, Gert Fröbe, Irina Demick, Bourvil, Curd Jürgens, George Segal, Robert Wagner, Paul Anka and Arletty.

Several cast members had seen action as servicemen during the war, including Albert, Fonda, Genn, More, Steiger and Todd, the latter having been among the first British officers to land in Normandy in Operation Overlord and participate in the assault on Pegasus Bridge.

These included Günther Blumentritt (a former German general), James M. Gavin (an American general), Frederick Morgan (Deputy Chief of Staff at SHAEF), John Howard (who led the airborne assault on the Pegasus Bridge), Lord Lovat (who commanded the 1st Special Service Brigade), Philippe Kieffer (who led his men in the assault on Ouistreham), Marie-Pierre Kœnig (who commanded the Free French Forces in the invasion), Max Pemsel (a German general), Werner Pluskat (the major who was the first German officer to see the invasion fleet), Josef "Pips" Priller (the hot-headed pilot) and Lucie Rommel (widow of Field Marshal Erwin Rommel).

Shot in a docudrama style (with captions identifying the different participants), the film opens in the days leading up to D-Day, depicting events on both sides of the English Channel.

On June 5, 1944, not wanting to keep his forces waiting any longer, Gen. Dwight D. Eisenhower, Supreme Commander of SHAEF, makes the decision to go ahead with plans to invade France through Normandy the following day after receiving a somewhat hopeful weather report.

British troops arrive in gliders to secure Pegasus Bridge, American paratroopers land scattered around Sainte-Mère-Église to defend a road that will be a vital artery for the invasion, and French Resistance and SOE agents conduct infiltration and sabotage work.

French producer Raoul Lévy signed a deal with Simon & Schuster to purchase the filming rights to Cornelius Ryan's book The Longest Day: June 6, 1944 D-Day on March 23, 1960.

[11] While Ryan developed the script, Zanuck also brought in other writers for cleanups for the various nationalities, including James Jones for the Americans, Romain Gary for the French, Noël Coward for the British and Erich Maria Remarque for the Germans.

[31] Richard L. Coe of The Washington Post called the film "a tingling, eye-gripping, fantastic picture" that "must rank as the screen's most massive battle epic", his only criticism being "the lack of perspective in depicting the German belief that the Normandy landings might not have succeeded had Hitler not taken a sleeping pill [...] 'The Longest Day' should have taken infinitely more care to put this German belief, however strongly held, into proper proportion".

[32] Brendan Gill of The New Yorker called the film "a tour de force of audio-visual verisimilitude," but confessed that "my emotions were hardly ever engaged, and I ended, rather to my embarrassment, by being bored".

He continued: "Mr. Zanuck made it all the harder for me to take this mock-documentary seriously by stuffing it with innumerable celebrated actors, most of whom make such fugitive appearances that the audience finds itself engaged in a distracting game of instant identification".

At its best, what comes across very strongly is the feeling of immense and careful organisation that went into the whole D-Day operation, the sheer crippling weight of noise, the simple fact that a lot of people died, and the sense of personal confusion and dismay of soldiers wandering alone through the countryside [...] But the film is, first and foremost, a spectacle, and therefore it has stars—a multitude of them, often with barely a line to speak, and usually with no real part to play".