This movie got an Oscar for the script (among the others, by Pietro Germi, the gifted director). However, the real importance of this movie can be demonstrated by saying that an entire genre, "la commedia all'italiana" (Comedy, Italian style) is named after this movie.
A major issue of this genre is to make fun of our traditions and culture (I am Italian) despite the radical changes our Country was having during those years ('60s, '70s).
The main issue of Neo-realism (Rossellini, De Sica, Visconti) was to describe the tragic reality of miserable lives after the catastrophic WWII. Then the Italian economic boom of the '50s drove Italy into modernity and wellness. Commedia all'italiana wanted to remind us that despite this modernity we are always the same Italians we were before, with all our intelligence but also with all our defects.
"Divorce, Italian Style" is set in the most 'conservative' place of Italy of that time, where traditions like family honor were still predominant despite all modernity. In the first shots of the movie we see an environment suffocated by the heat of the Sicilian climate. People spend part of the day in their apartments waiting for the cool evening. This motionless environment is highly metaphoric, as it shows that nothing really changes in this land, suffocated by the weight of old traditions. Probably this is not so true today, but at that time certainly was.
However, don't be scared by this introduction. The movie is FUN and it turns into a fast-paced rhythm shortly.
The protagonist loves his cousin and wants to marry her, but he is already married. So he plans to murder the wife, pretending to do that for a 'legitimate' defence of honor. What is amazing is that all the village, all the people in the movie support murder for the honor of the family. They even induce him to kill. And what is sad, is that the law at that time was really soft for those types of murders.
To summarize this movie has these characteristics: 1) VERY FUN. You can't stop laughing even if the script is tragic (this is a characteristic of masterpieces) 2) WELL ACTED: Marcello Mastroianni gives one of his best performances. Stefania Sandrelli is beautiful as ever, Marcello's wife is ugly and a nuisance as her role imposes, and Leopoldo Trieste is another great actor of Italian cinema.
3) WONDERFUL STORY: the script won the Oscar and it is truly very intelligent 4) SOCIALLY COMMITTED: it is an accusation of a wrong law that supports a wrong tradition (the law was changed shortly after).
I give this masterpiece a 10 out of 10, and I strongly recommend it to everyone.