His death was announced on the Web site of the Tonino Guerra Cultural Association.
In a screenwriting career covering a half-century, Mr. Guerra earned three Academy Award nominations and had a long partnership with Antonioni. Their first collaboration, the enigmatic "L’Avventura" (1960), was also the film that put Antonioni on the world cinema map and forever linked him with the quintessential modernist theme of alienation.
In the fruitful decade that followed, Mr. Guerra and Antonioni worked together on "La Notte" (1961), "L’Eclisse" (1962) and "Red Desert"(1964), then ventured abroad to capture the restless energy of youth-culture epicenters: swinging London in "Blow-Up" (1966) and radicalized, disillusioned California in "Zabriskie Point" (1970).
They collaborated on 10 films in all, including Antonioni’s final one, a short called "The Dangerous Thread of Things." Part of the 2004 omnibus "Eros," it appeared along with short films by Steven Soderbergh and Wong Kar-wai.
Most major film careers in Italy from the second half of the 20th century intersected at some point with Mr. Guerra’s. He wrote three films with Fellini, including "Amarcord" (1973), which drew on their shared memories of growing up in the Emilia-Romagna region. He worked with several generations of his countrymen, including Francesco Rosi ( "Lucky Luciano" ), Mario Monicelli ("Casanova ’70"), the Taviani brothers ("The Night of the Shooting Stars"), Marco Bellocchio ("Henry IV") and Giuseppe Tornatore ( "Everybody’s Fine" ). And he played a key role as Italian cinema moved away from the neo-realism of the postwar years to incorporate stylization and artifice.
His Oscar-nominated screenplays were for "Casanova ’70," "Blow-Up" and "Amarcord." Outliving many of his best-known collaborators, he received numerous honorary awards in his later years, including lifetime achievement awards at the Venice Film Festival in 1994, the European Film Awards in 2002 and the David di Donatello Awards (the Italian Oscars) in 2010. He also received the Writers Guild of America West’s Jean Renoir Award for Screenwriting Achievement in 2011.
In the second half of his career Mr. Guerra’s affiliations with Tarkovsky and Angelopoulos — who could be considered Antonioni’s spiritual heirs — sealed his reputation as a writer with a questing, poetic sensibility, a hand-in-glove fit for directors who specialized in existential matters and the mysteries of interior life.
His close friendship with Tarkovsky led to one co-written screenplay, for the 1983 film "Nostalghia," which describes the meeting between a Russian poet and an Italian madman, and one co-directed documentary, "Voyage in Time" (1983).
Mr. Guerra’s long association with Angelopoulos began with the 1984 film "Voyage to Cythera," which won the best screenplay award at Cannes, and continued until Angelopoulos’s last completed film, "The Dust of Time" (2008). It was also the last film Mr. Guerra worked on, at age 88. (Angelopoulos died in January.)
Antonio Guerra was born to a peasant family on March 16, 1920, in Santarcangelo di Romagna, near Rimini. His father was a fisherman and fishmonger. In an autobiographical essay published in 1985, he wrote that his mother was illiterate and that he taught her to read and write.
Captured and sent to a German concentration camp during World War II , Mr. Guerra started writing poetry in the Romagnole dialect. His first collection of poems was published in 1946 under the title "I Scarabocc" ("Scribblings").
After working as a teacher for a few years, he moved to Rome in 1952 and fell into film circles through a friend, Elio Petri, who would himself become a writer and director.
Mr. Guerra’s first screenplay credit, shared with Petri and several others, was on "Men and Wolves," a 1956 film by Giuseppe De Santis. Mr. Guerra devoted most of his energies to screenwriting in his 30s and 40s, but after turning 50 he resumed writing and publishing poetry (in his local dialect) and occasionally fiction (in standard Italian).
He is survived by his second wife, Lora, and a son, Andrea Guerra, a film composer.
Mr. Guerra was sometimes asked to reconcile his roles as poet and screenwriter. "My poems were an essence of images," he said in an interview when he was 80. "They had the cinema inside them before I started working for it."
In a preface to a collection of his screenplays, Antonioni described his collaborative process with Mr. Guerra as one of "long and violent arguments," which he found "helpful." Their rapport, he added, allowed him to "keep quiet as long as I wish without feeling embarrassed."
"And for this he’s even more helpful," Antonioni wrote.
Angelopoulos likened Mr. Guerra to a devil’s advocate and a psychoanalyst. But the most tangible record of Mr. Guerra’s collaborative role can be found in "Voyage in Time," which chronicles his travels through Italy with Tarkovsky, scouting landscapes and exchanging thoughts on life and cinema, as the screenplay for "Nostalghia" took shape in their heads.
Mr. Guerra’s own ideas about screenwriting were modest. He described a script in utilitarian terms, as "something dead," "a structure you need for a film." But he also admitted, "I believe I have given a little bit of poetry to all the directors I worked with."
He continued to write into his 80s but also found time to paint and create sculpture. And he became a household face in Italy as the star of a series of commercials for an electronics retailer, delivering the catchphrase "Optimism is the perfume of life."
A trailer for a documentary in progress on his life and work, titled "3XTonino," opens with a quote from Mr. Guerra on screen. It reads: "Death isn’t that awful. After all, it comes only once."
