Before Federico Fellini's films evolved into the often whimsical plots of his later work, his early films were very much rooted in the social realism that characterized the immediate post-war period in Italian cinema.
"I Vitelloni" mines similar territory to, and anticipates, Luchino Visconti's 1960 "Rocco and His Brothers" in that it focuses on the lives of young men in the the Italian provinces, the title being slang for a "loafer" or more literally "Bullocks".
The loafers here, a group of men, perhaps in their late twenties though they look older, spend their time chasing women, and generally idling about in a provincial town where prospects beyond acceding to their parents wishes of getting hitched and starting a family, are limited due to the economic conditions in post-war Italy.
By choosing to tell a story with an ensemble cast of different characters rather than a "hero", Fellini could tell a story that is possibly partly autobiographical but not as obviously as his later film "81/2" and so we get to see the struggles of each character and there is no clear cut "hero".
In fact "anti-hero" would be a better description rather in the way that in Visconti's film we follow the arc of Simone, who is a "bad boy" whose dynamic with his younger brother Rocco, the "good boy", is anticipated in "I Vitelloni" in the relationship of two of the group, Fausto, the group's "Lothario", who manages serial affairs with various women in the town, and Moraldo, an aspiring playwright who ultimately comes to the conclusion that his future exists somewhere else.
This is very relatable film with universal themes that could be applied to any society in any country, in any era - young people with dreams, being tied down by responsibilities like family, escaping home to seek a fortune, facing moral dilemmas that result from ambition and so on, and the film is part of a trio of social realist films written and directed by Federico Fellini that include the groundbreaking "La Strada" and later, "Nights of Cabiria".
Both "I Vitelloni" and "Rocco & His Brothers" were scored by Nino Rota and a footnote on the films Wikipedia page indicates how influential the film has been, attracting fans such as Stanley Kubrick, who listed it as one of his top 10 films, and inspiring George Lucas' 1973 film, "American Graffiti".