Which actor except Jack Nicholson could have played Randle Patrick McMurphy in "One Flew Over the Cuckoo's Nest"? Gene Hackman and Marlon Brando both passed on the role. Burt Reynolds was a candidate. But Nicholson is McMurphy, the man who put the Man into "manic" - the charmer only a lobotomy could wrestle into submission. Never mind that in Ken Kesey's best-selling novel, McMurphy is a stocky redhead, with a badly stitched gash across his cheekbone and nose, which means that if the director Milos Forman had been true to the novel, Mr. Nicholson could have received Oscar nominations two years in a row for tough guys with bloody noses.

Mr. Nicholson was denied the best-actor prize for his role as a Los Angeles private eye in "Chinatown," but he won in 1975 with "Cuckoo's Nest." The film celebrates its 25th anniversary this month and has held up quite well. Mr. Nicholson's performance has not aged at all - even his in-patient coiffure is hip enough for MTV Movie Awards night. Mr. Forman made so many sweeping changes from the novel that the book's author refused to see the movie. But a quarter century later, those very changes help the movie seem almost eerily contemporary.

The story of this film's troubled path to the screen, and its ultimate triumph, is the kind of scrappy-little-movie-that-could story that Hollywood loves. Kirk Douglas bought the rights to the 1962 novel, played McMurphy on Broadway in 1963, then spent years having studios assure him that audiences did not want to watch a movie about insane asylums. Admitting defeat, he gave the rights to his son Michael Douglas, who got the producer Sol Zaentz and Mr. Forman involved. But even with Mr. Nicholson on board, studios weren't interested.

Made on a $4.4 million budget, "One Flew Over the Cuckoo's Nest" was the seventh-highest-grossing movie ever when it came out, and has gone on to gross more than $320 million worldwide, Mr. Zaentz reported. It has strange international pockets of downright worship (in Sweden it ran in theaters for 11 straight years). In 1975 it became the first film since Frank Capra's 1934 "It Happened One Night" to sweep five top Oscars, beating out "Jaws" and "Nashville" for best picture.

In one way, of course, "One Flew Over the Cuckoo's Nest" continues a line of American movies celebrating the romance of rebellion. We like our heroes lone. Beneath those tough rib cages beat vulnerable hearts. From "Rebel Without a Cause" to "A Thousand Clowns," men who knew who they were and weren't afraid to say so defied conformity. Mr. Nicholson's seductively confrontational persona had been set with "Easy Rider" in 1969 and further refined the next year by the famous scene in "Five Easy Pieces" in which the waitress in the diner won't serve him toast so he demands a chicken salad sandwich - without the chicken salad. "They're telling me I'm crazy," McMurphy announces, "because I don't sit there like a goddamn vegetable. If that's what being crazy is, then I'm senseless, out-of-it, gone-down-the-road wacko, but no more and no less."

In the more sentimental versions of this visionary madman formula (as in the 1966 cult film "King of Hearts," starring Alan Bates), the loonies turn out to be saner than their adversaries. Kesey's novel served as a baby-boomer counterculture bible. In Vietnam and Watergate days, the conspiracy that Mr. Kesey dubbed "the Combine" was interchangeable with the buzzword "Establishment." It was They who were out to get Us.

Mr. Kesey's novel is not really quite that ideologically simplistic, since it's narrated by Bromden, a k a Chief Broom or Chief, a giant American Indian patient dismissed for decades as deaf and dumb - a hallucinating, unreliable narrator if ever there was one. But the film eliminates Chief as storyteller. "The first- person mode of narration," Mr. Forman writes in his 1993 autobiography, "Turnaround," "is better suited to literature than to film. Film generally views the world from the outside, from a more objective vantage point."

An "objective" film about madness? At first glance it seems impossible. As Mr. Kesey tells Charles Kiselyak, whose 1998 documentary, "Completely Cuckoo," looks at the film's creation, "They wanted to do `Hogan's Heroes,' and I wanted to do `The Cabinet of Dr. Caligari.' " But the originality of Mr. Forman's film lies in just that striving for objectivity, in its refusal to color the institution or its people with too much easy drama.

By 1975 there had already been quite a bit of the avant-garde, hand- held camera documentary approach, like Frederick Wiseman's influential "Titicut Follies" (1967). But when appropriated by feature films, the documentary style generally meant portraying the truth as harsh and stark - in itself a dramatic coloring. The scene of McMurphy's shock treatment focuses on his face, rejecting the accurate but clichéd arms- and-legs-flailing shot. Although the action takes place almost entirely indoors, the film feels neither unrelentingly bleak nor airless. Bizarre as many look, the patients (including Christopher Lloyd, Will Sampson and Brad Dourif in their film debuts) don't seem like shallow, static nut cases. Mr. Forman never quite allows McMurphy to become a simple martyr. And he never paints Nurse Ratched as McMurphy's Evil Executioner, either.

Nowhere is the complexity of the film's characterization more striking than in Louise Fletcher's best- actress Oscar-winning performance as Nurse Ratched. According to "Completely Cuckoo," the role was turned down by five stars - Ann Bancroft, Colleen Dewhurst, Geraldine Page, Ellen Burstyn and Angela Lansbury - before Ms. Fletcher was cast a mere week before shooting began. In the novel, Ratched is a huge-breasted, tiny-mouthed Valkyrie. Fletcher humanizes the part. We see that she actually believes she's doing good. Chief's claim that the patients, all men, are "victims of a matriarchy" would not have aged very gracefully on screen. Nor would Chief's overt and unapologetic racism. Mr. Forman doesn't transform the phalanx of black orderlies into a Rainbow Coalition. But he declines to show orderlies "performing all sorts of horrible crimes" on sleeping patients, as they do in the novel.

Mr. Forman can't be accused of sugar-coating the Combine. A filmmaker who had lived under Communist rule in Czechoslovakia, he came to the material with intense feelings about bureaucracy. "This is a movie about Czech society, about everything I know," he tells Mr. Kiselyak. Mr. Forman appreciates the roots of oppressive regimes - which at least at the onset appeal with their promise of comfort, order and protection.

As Susanna Kaysen writes in her best-selling memoir about her institutionalization, "Girl, Interrupted" (also a 1999 movie), "For many of us, the hospital was as much a refuge as it was a prison"; paradoxically, "in a strange way we were free." So when "Cuckoo" inmates commandeer a boat and escape for a fishing trip, we see that for all their jubilance the boat is merely spinning in circles. When, in the final scene, Chief (Sampson) escapes into the horizon, Mr. Forman makes sure that the landscape appears threatening as well as liberating.

Made in what many critics deem a particularly fertile period for Hollywood films, "Cuckoo" coincided with a time of creative changes in psychiatric treatment. The film was shot on location at the Oregon State Mental Hospital in Salem. Dean Brooks, the hospital's actual superintendent, played the film's psychiatrist. Mr. Brooks had been profiled in Life magazine after taking 51 patients on a two-week water-rafting trip. So it was hardly a stretch for him to get 89 patients on payroll as assistants to the film crew. One patient was so emboldened by the responsibility that he permanently lost his stutter.

In "Completely Cuckoo," which had its premiere at the 1998 Rendezvous With Madness Film Festival in Toronto, Mr. Kiselyak tours the current grounds with the now retired Mr. Brooks, who notes that there are fewer patients strolling around behind the ominously high new wire fence. But that's partly because, to a large extent, only what the Chief called "the chronics" are left.

"Cuckoo" is decidedly pre-Prozac. In the film, the patients complain about being forced to take their zombifying meds. Mr. Forman could not have anticipated the vast improvements in psychiatric drug treatment or the troubling changes in mental health care protocol and benefits - now the Combine is less likely to err by keeping a patient forever than by scribbling a prescription and booting him out.

But the brilliance of the film is precisely that its subtle, empathetic realism outlives such vicissitudes. In one scene, Mr. Forman has the patients ignore a television set on which an announcer talks about the possibility of the Berlin Wall coming down. Whatever happened or will happen in the world beyond, those men are imprisoned in that locked ward. And we're still rooting for them, still as itchy as they are to witness McMurphy's next wild move.

Lisa Zeidner is a professor of English at Rutgers University. Her fourth novel, Layover, was recently issued in paperback.

Copyright The New York Times, 1 December 2000.