TELLURIDE, Colo. — Orson Welles was on the line. “What are you doing Thursday?” he asked.

It was 1970, and the “Citizen Kane” director had called Peter Bogdanovich to ask him to appear in his latest film, “The Other Side of the Wind.” Yes, he knew that Mr. Bogdanovich was stretched thin. Just drop by the set on Thursday, Welles insisted. The whole movie was only going to take a few weeks to shoot — tops.

Forty-eight years later, “The Other Side of the Wind” has finally arrived. It was shown for the first time in North America on Saturday at the Telluride Film Festival, where two new documentaries about the herculean efforts to finish the film were also screened. “It’s sad because Orson’s not here to see it,” Mr. Bogdanovich, 79, said from the stage of the Palm Theater here. “Or maybe he is.”

Cinema buffs had almost given up on “The Other Side of the Wind,” which Welles left unfinished upon his death in 1985. It is known as one of the most famous movies never released, held up by warring rights holders and never-ending financial troubles, including a failed funding effort by a relative of the shah of Iran.

No lesser a force than Frank Marshall, one of the most powerful producers in Hollywood, had been leading the salvage effort. Mr. Marshall, 71, made his name by making the impossible possible — shutting down the Las Vegas Strip to shoot “Jason Bourne,” staying calm the time Steven Spielberg asked him to find 10,000 additional snakes for a scene in “Raiders of the Lost Ark,” figuring out how Clint Eastwood could crash a jetliner for “Sully.” If he couldn’t pull the film over the finish line, who could?