The really successful adaptation is the one that demotes the "original" to second-class celebrity. "Hamlet" was a pre-Shakespeare play; "La Bohème" was a book. Mention the words "Godfather," "Pirates of the Caribbean" or "Titanic," and people are more likely to think of a movie than they are a novel, amusement-park ride, or sinking ship.
Say the word to certain people of a certain age, and there's a chance they'll revisit in their minds the mutating plastic robot toys that contributed to many a joyful childhood -- and a global entertainment empire built on books, games, films and TV series.
But most people will simply conjure up those loud and lucrative movies from director Michael Bay, the fourth of which -- "Transformers: Age of Extinction" -- opens June 27.
"It's kind of true," said the Irish actor Jack Reynor, who, along with Nicola Peltz, is one of the fresh faces in a now- venerable franchise. "The whole thing started 30 years ago in Japan, but Michael Bay has made "Transformers" synonymous with American culture. It's a whole different animal."
Reynor plays Shane, the boyfriend of Tessa Yeager (Peltz) who is the daughter of Cade Yeager (Mark Wahlberg), the auto mechanic who discovers the dormant Optimus Prime within a derelict tractor-trailer. That sets off a scheme in which an industrialist madman (Stanley Tucci) tries to dominate the world through a manufactured line of Autobots and Decepticons (shades of Hasbro!).
Reynor -- who with the departure of the troubled Shia LaBeouf has assumed the franchise's male ingénue position -- said the making of "Age of Extinction" took him a long way from County Wicklow.
"It's been kind of a crazy experience," he said, "making that big leap from independent Irish films to Hollywood blockbusters. But at least there haven't been any guys showing up at my hotel with full-on Bumblebee outfits."
Peltz, whose biggest previous role was in "The Last Airbender," called "T4" a story that -- in addition to being about robots and destruction -- is about "normal people in extraordinary situations": The casting of Wahlberg, as a father protecting his family, marks a dramatic shift in the dynamic of the "Transformers" story line and seems intended, maybe, to target an older demographic. (The screenplay is by Ehren Kruger, who wrote the last two "T" movies as well as the upcoming "Transformers 5.")
"Not explicitly," said Lorenzo Di Bonaventura, who has produced all the "Transformers" movies. "But by having Mark Wahlberg in it, it automatically puts the hero in a position of having a family and, in this case, of taking the fight to the bad guys and making that believable. Shia was great, but not old enough, I think, to quite pull that off. Audiences wouldn't really accept him doing what Mark does."
Di Bonaventura, extolling the technological edge of his new film, said, "There are at least three extraordinary shots in this film that are as big as anything I've been involved with in my career," which has included "Salt," "RED," the "G.I. Joe" films and "Jack Ryan: Shadow Recruit."
"It's a credit to Michael pushing the technology," he said. "And a credit to his imagination." What added a wrinkle to the "T4" process was its lengthy shoot in China, which provided an education for everyone.
"This was a big cultural change," he said. "In China, it's just a different way of doing business, and you learn it all on the fly."
He compared it to shooting in this nation's capital. "In D.C., there are nine different police departments -- and I exaggerate only slightly. If you want to shoot on the mall, you deal with the park police. If you want to shoot on the edge of the mall, you deal with a different department." He said on one film it got so complicated, they left.
So it was easier to shoot in China than in Washington? Di Bonaventura just laughed.
So did Reynor, when asked about his transition from such films as Lennie Abrahamson's relatively micro-budgeted "What Richard Did" (2012), which was the actor's breakout, and a megalithic corporate entity like "Transformers: Age of Extinction."
"I'm trying to keep a level head," he said.
But there's a serious side to the film, he added, and a human one. "What makes the film more than anything else is that there's a much greater sense of threat," Reynor said. "It's grittier; there seems to be more to lose. And that's a good thing."
It might even be good for human actors. "At the start of the film," he said, "the Autobots have lost all their respect for humanity, and it is through this relationship with Mark, Nicola and myself that we try to restore their faith in us. There is this really huge potential for massive, massive destruction on a human level, and it's our characters who try to sell that intensity.
"It's great to have giant robots," he added. "But you need human characters to get that intensity across."
Michael Bay's blockbusters
Most people probably think of director Michael Bay as a Renaissance man: He not only makes big, loud movies with robots ("Transformers," "Transformers: Revenge of the Fallen"), he makes bigger, louder movies with robots ("Transformers: Dark of the Moon" and now "Transformers: Age of Extinction"). But, seriously folks, there are other big guns in his oeuvre, where the earliest entries were music videos, advertisements and the Playboy Kerri Kendall Video Centerfold of 1990. Highlights of his rap sheet:
PEARL HARBOR (2001): Wood floats, so it's hard to understand why Ben Affleck and Josh Harnett seem so worried during Bay's alleged "tribute" film that, legend has it, cost more than the actual 1941 airstrike on Pearl Harbor.
BAD BOYS (1995) & BAD BOYS II (2003): These buddy-cop comedies did a lot of good for the careers of Will Smith and Martin Lawrence, but their audiences were bombarded by the pyrotechnical excesses of a director who couldn't leave well enough alone.
THE ROCK (1996): Thickheaded without being oppressive, this may be Bay's best movie. The thriller teams a chemical-weapons expert (Nicolas Cage) with a former British spy (Sean Connery) who are supposed to thwart an insane general (Ed Harris) who has taken 80-odd hostages on the prison island of Alcatraz and is threatening to gas San Francisco.
THE ISLAND (2005): Lincoln Six Echo and Jordan Two Delta (Ewan McGregor, Scarlett Johansson) don't know it, but they are "harvestable" humans, sprung from the DNA of people who are going to use them for replacement parts.
PAIN & GAIN (2013): Mark Wahlberg, Dwayne Johnson Anthony Mackie and a bunch of other special effects are featured in this story of professional bodybuilders who get caught up in a kidnapping scheme that goes terribly wrong. Along with a few other things.