In Ready for My Closeup (Grand Central, Aug.), the film professor takes readers behind the scenes of the 1950 film Sunset Boulevard.

Why write a book about a 75-year-old movie?

When I started teaching film history, I’d show Sunset Boulevard and students always reacted so strongly to it. They really identified with the characters of washed-up movie star Norma Desmond and down-on-his-luck screenwriter Joe Gillis, especially with the way that Desmond bends herself out of shape to look beautiful and young. Students said that they felt the same kind of pressures. When you’re about to graduate from college, there’s anxiety about what’s going to happen. University is a coddling place, and suddenly you’re thrown out onto the pavement and have to make your way. I think the Gillis story of selling your soul in order to stay in the game brings up existential questions that students can connect with. You wouldn’t think there’d be that generational link going on, but there is.

You contend that Sunset Boulevard embraces an “unsettling” mix of genres. Can you elaborate on that?

The film opens with an intense action picture soundtrack that would have been understood at the time as typical of a crime thriller, but when Gillis starts telling his story and the narrative flashes back to him looking for work, we suddenly step into a Hollywood satire. We return to the thriller mode when Gillis runs away from men who want to repossess his car before we shift to the horror genre, but the movie makes that pivot with little musical cues that say, don’t take this too seriously. I think anybody who appreciates Sunset Boulevard has to appreciate the alacrity with which screenwriters Charlie Brackett and Billy Wilder were able to jump from genre to genre and back again.

How do you reconcile your claims that the film is both a “love letter” to and a “self-critical examination” of Hollywood?

The standard reading of Sunset Boulevard is that it represents Hollywood’s scathing view of itself. The movie contains a lot of Hollywood satire, particularly in the first two acts, when Gillis is trying to sell his screenplay. Everybody remembers that as the tone of the whole movie, but there are other scenes, like when Gillis and script reader Betty Schaefer go walking on the Paramount back lot at night, where Brackett and Wilder celebrate film’s ability to sweep us off our feet, take us to imaginary worlds, and engage us in the creative process. The people who made the movie loved Hollywood. The bitterness comes from no longer being in demand and having to face the very human condition of not being wanted anymore, whether you’ve aged out or been blacklisted. There’s an underlying melancholy throughout Sunset Boulevard over that kind of loss, but you’re only getting half the picture if you call the movie an attack on Hollywood.