This year is the 75th anniversary of Casablanca, the bittersweet World War II romance whose every line and plot point is a classic: Humphrey Bogart giving up Ingrid Bergman for the good of the cause; Dooley Wilson reassuring the crowd at Rick’s that the fundamental things still apply; and Captain Renault deciding to turn a blind eye and round up the usual suspects. Noah Isenberg, director of Screen Studies at The New School’s Eugene Lang College of Liberal Arts, has marked the occasion by publishing We’ll Always Have Casablanca, an insightful, highly entertaining film history. Isenberg spoke with the National about the real-life origins of the Casablanca story, what makes the movie’s screenplay so legendary, and why Bergman called Casablanca “mystical.”

1. What drew you to Casablanca as a subject for a book — and why do you think it’s important today?

It was in conversation with critic Molly Haskell that I came up with the idea for the book. She’d just finished her book Frankly, My Dear, on Gone With the Wind, and as the 75th anniversary of Casablanca was creeping up on the horizon, the time seemed particularly ripe for a reappraisal of what is arguably Hollywood’s most cherished movie. To test the waters, I published an op-ed piece in the Wall Street Journal on the occasion of the film’s 70th anniversary, over Thanksgiving weekend 2012, and the response was overwhelmingly positive. One of the reasons for Casablanca’s extraordinary staying power is that despite being so much of its age, as perhaps the greatest wartime drama ever made, it’s still very relevant today.

2. You tell a backstory that few moviegoers know, that the writer of the play the movie was based on, Murray Burnett, visited a real bar in Europe filled with people fleeing Nazis — and a black piano player from Chicago. How fact-based is Casablanca?

I think you’ve just touched upon another reason for the film’s enduring quality — namely, the remarkable intermingling of history and fiction, and the patina of authenticity that is bestowed upon the film as a result. So, yes, Burnett’s real-life experience with the refugee trail and all that he witnessed that fateful summer of 1938, when helping his wife smuggle valuables out of Vienna, informs the film, as do the innumerable experiences of of the émigré cast members who had lived through Hitler’s stunning ascent in Europe.

3. In addition to being a great movie, Casablanca is a great screenplay — #1 in a 2001 Screenwriters Guild ranking. What makes the screenplay — which was in large part written by the famed duo of Julius and Philip Epstein — so effective and powerful?

You have some of the very best writers of the studio era behind the script. First, the Epstein twins, Julius and Philip, who were known around Hollywood for their singular talents at adapting stage plays and also for their martini-dry wit. They’re responsible for most of the caustic zingers—those lines that continue to be quoted with staggering frequency—in the film. Then, the more politically minded Howard Koch, who would go on to write Mission to Moscow, also directed by Michael Curtiz, for Warner Bros. a year later, gave the screenplay a sense of urgency. And Casey Robinson, who had written the blustery romance Now, Voyager for producer Hal B. Wallis the previous year, sprinkled a little pixie dust (uncredited) on the romantic strand of the story. The unproduced stage play by Murray Burnett and Joan Alison, Everybody Comes to Rick’s, also provided more than a mere foundation for the script. It’s a winning combination no matter how you look at it.

4. Casablanca was filmed with World War II raging — and the fate of the world very much up in the air. How much do you think the studio, the writers, and the actors intended for the movie to be not just entertaining, but a political act, striking a blow against Nazism?

I think that especially the refugee actors—those who fled the Hitler and Vichy regimes—felt that the stakes were unusually high. Hungarian-born director Curtiz, who had family still stranded in Europe, also understood the need to mount resistance and to fight the evils of Nazism. Finally, the Warner brothers themselves, in particular Jack and Harry, were unusually outspoken, even when it was unpopular to take such positions, about the need for the U.S. to become more deeply involved in the battle against fascism and racial persecution. They felt that their movies ought to reflect the political and historical events as they were unfolding across the Atlantic.

5. You write about a little-discussed aspect of Casablanca— that the role of Sam, played by the incomparable Dooley Wilson, was a major step forward for African-Americans in Hollywood. What was it about that character and Wilson's portrayal of him was such a break with the past?

Sam (Dooley Wilson) is not merely an entertainer, with that velvety voice of his, and the keeper of Rick and Ilsa's torch song, "As Time Goes By"; he’s also Rick’s dear friend, his confidant and traveling companion. Rick treats him as a peer, protects him, drinks with him—the scene in the Parisian flashback, with Rick, Ilsa, and Sam all sharing a champagne toast is notable in this regard—and he has real trouble leaving him behind. I became most aware of the advances made by Wilson in his portrayal of Sam when reading the review of the film in the Amsterdam News, a black-owned newspaper in New York, which extolled the leap forward from playing Pullman porters, cooks, valets, and other subordinate roles.

6. You open We'll Always Have Casablanca with a quote from Ingrid Bergman saying there is something “mystical” about Casablanca. What do you think makes it such an enduring, and haunting, film?

Mysticism is something that doesn’t lend itself easily to scientific classification or definition. Similarly, the enduring qualities of Casablanca cannot always be readily explained. When critic Bosley Crowther of the New York Times reviewed the film, soon after it opened at the Hollywood Theatre on Thanksgiving Day 1942, he said it’s a “picture that makes the spine tingle and the heart take a leap.” I think, already then, he sensed its mystical allure, the same allure that Bergman noted decades later—that elusive emotional connection that it has with audiences over the ages.