Classic films give us cineliteracy. They change the way we look at every movie afterward, how we talk about films, and they grant us entry into a new way of seeing the world and the movies about it.

Movies like “Bicycle Thieves (Ladri di Biciclette)” were tradiationally passed around like a secret code, seen in film societies and college courses where the greatest of the Italian “neorealist” films altered the way we view cinematic “reality” the moment we saw it.

And revisiting such classics, even in our easy-access, instant-gratification Golden Age of Streaming, is like remembering a first love and the moment you became aware of that emotion.

Vittorio De Sica’s 1948 masterpiece is stunningly simple, beautifully stark and heartbreaking in the bluntest sense. It’s about poverty, a family struggling, Italy in throes of a post World War II reckoning — deep, lingering depression. And it’s about a father and the son who worships him, literally never taking his eyes off his mentor, always looking up at him when they’re together.

Antonio dotes on little Bruno, until that is, the bicycle he needs for his long-sought-after job is stolen on his first day at work. The bicycle means getting ahead, planning for a better future, better housing, food security and financial solvency. And when it’s gone, Antonio’s wholly-relatable obsession with recovering it has him neglecting a little boy imperiled by the inattention, wounded by the side of his father that he now sees.

Lamberto Maggiorani didn’t act in many films. But his intense blend of panic and despair as Antonio carries “Bicycle Thieves,” a lean, streetwise narrative about a man’s dogged search for his 1935 Fide, swiped while he was up a ladder at his new job, hanging posters of Rita Hayworth and others all over Rome.

And little Enzo Stailo, as natural at age eight, when he filmed “Thieves,” as any child actor before or since, is immortalized in a movie that captures a child’s commitment to his first role model as it is tested and tainted by the trauma of what happens to their family.

Alessandro Cicognini’s tender, sentimental score tugs at the heartstrings as we see Antonio selected for a job in a sea of men who have also been waiting since the war’s end for work. “Hope” is set to music.

We don’t understand Antonio’s concern about the “no bicycle, no job” (in Italian with English subtitles) conditions for employment. But we grasp the relief in his eyes and the dogged determination of wife Maria (Lianelli Carell) as she gathers up the family sheets and they parade down to the warehouse-sized pawn shop, which is always a mob scene during hard times like this. Antonio’s bike is in hock and they’re retrieving it.

Little Bruno knows every millimeter of it, as it’s his job to clean and prep the Fide for work. He’s been a breadwinner for the house in his own way, as Dad drops him off at the Esso station, where Bruno cleans up, on his way to his new posters-hanging job.

Antonio needs the bike so that can carry rolled up posters on the luggage rack, a bucket of glue on the handlebars and a ladder over his shoulders. A bit of brief instruction, and he’s off.

He doesn’t notice the creep (Vittorio Antonucci), working with an accomplice, who cases the bike, sizes Antonio up and grabs it. Noble Antonio doesn’t know the other guy “helping” him chase the thief is in on the hustle, just here to slow him down.

Maggiorani lets us see the deflating realization of what this simple wrong will mean to himself, his family and their lives. He’s reluctant to tell Maria, seeking first the connected garbageman and neighborhood theatrical impressario Baiocco (Gino Saltamerenda) for help. Through him, our hero and his devoted son will visit the broad-daylight underbelly of Rome’s bike chop-shop culture — flea markets filled with bike parts which little Bruno can identify, a possibly repainted frame that Antonio can ID for the otherwise useless police.

Half a dozen other screenwriters pitched-in with De Sica to bring Luigi Bartolini’s novel to life. But it is the visual divine comedy/inferno of a broken and broke Rome that makes the picture.

Father and son trek from piazza to river to street markets and even a rescue mission/food kitchen in pursuit of the bicycle and the “ladri” (thieves) who took it. Clues and pursuits are set against the early morning buzz of manual labor and returning postwar commerce. A rainstorm interrupts a parade of novitiate divinity students in their drenched, brimmed Capello romanos.

They are German, which puzzles Bruno and reminds Antonio that the thief was a street punk wearing a German Wehrmacht cap.

Over 75 years after its release, “Bicycle Thieves” still compels you to shout at the screen, urging Antonio to take care of his kid as he frantically forgets him in his heedless, hurtling search. Finding suspects who might lead him to his quarry makes you want to shout “SLAP him until he talks,” even now.

But those are the moments Antonio is most aware that his animated, plucky, talks-with-his-hands bambino is watching.

“Bicycle Thieves” is such cinematic common currency that it is mentioned in almost any movie about a movie lover — Woody Allen’s “Stardust Memories” to Robert Altman’s “The Player.” Maurizio Nichetti’s “The Icicle Thief” comically sends it up, and yet also worships De Sica’s masterpiece.

Because it’s still worth worshipping. The Method is most credited with changing screen acting. But the Italian neorealists and their actors didn’t know Stanislavsky. And this film, in particular, is a shock-to-the-acting system when compared to almost everything that preceded it into cinemas.

Seventy-five years after its conception, filming and release, the first film listed at the top of that inaugural Sight & Sound Magazine poll of critics as The Best Film Ever Made back in 1952 remains essential viewing for any lover of film. It’s a great film — among the greatest, and if you want to have an informed conversation about any movie any where in the world, “Bicycle Thieves” is the cornerstone work of your film cinema education.

And right now it’s on the classic film buff’s best friend, Tubi, for free. What are you waiting for?

Rating: unrated

Cast: Lamberto Maggiorani, Lianelli Carell, Gino Saltamerenda, Vittorio Antonucci and Enzo Staiola

Credits: Directed by Vittorio De Sica, scripted by Oreste Biancoli, Suso Cecchi D’Amico, Adolfo Franci, Gherardo Gherardi, Gerardo Guerrieri, Cesare Zavattini and Vittorio De Sica, based on a novel by Luigi Bartolini. A Produzioni De Sica on Tubi.

Running time: 1:29