The cognescenti burn a lot of electrons typing out odes to the adored, enduring superhero of science fiction, Philip K. Dick. But the ongoing appeal of a writer who arrived on the scene right after the author of “Do Androids Dream of Electric Sheep” had his moment is just as fascinating.

Michael Crichton was a to-the-manner-born Harvard educated doctor who decided medicine wasn’t for him, so he wrote “Jurassic Park” and wrote and directed “Westworld,” some of the most enduring franchises in cinematic science fiction.

“Andromeda Strain,” TV’s “ER,” “Runaway,” he was prolific, an Emmy winning writer and show-creator, a writer-director of films as disparate as the classic “original” caper tale, “The Great Train Robbery” and “Coma,” a paranoid thriller set in the mysterious world of Big Medicine, a subject ripe for conspiracy theorizing.

Critchton had his finger on the pulse of the culture and its connection to science for most of his life. Movies based on his books (“Looker,” about cosmetic surgery’s end game) and “Rising Sun” (about “The Japanese Century,” which lasted about 8 years) weren’t all hits.

But the man did his research and did a pretty job of convincing us that dinosaurs could be brought back to life, that theme park animatronics could reach a dangerous level of sophistication and sentience and that a first encounter with alien “life” would probably be a virus.

“Coma” was based on a Robin Cook novel that was right in Crichton’s wheelhouse. A hospital and its corrupt leadership conspire to knock people into comas for organ harvesting to the highest bidder. Be honest. That sounds a LOT less far-fetched today than it did 45 years ago.

It’s a Geneviève Bujold star vehicle, allowing this acclaimed Canadian actress primacy in beating Sigourney Weaver (“Alien”) to the punch in playing a heroine fronting a major sci-fi thriller.

“Coma” is a movie made memorable by that one iconic image — naked coma victims, dangling from wires on life support, their lives “preserved” ostensibly until something could be done for them, or even to them when “society” changed its minds about them.

The medical profession? We’re just taking “care of the vegetables,” one cynically notes.

Dr. Susan Wheeler (Bujold) is a surgeon-in-training at Boston Memorial, where her doctor boyfriend (Michael Douglas) is in line to be head internist. When Susan’s friend (“Bond girl” Lois Chiles) comes in for an abortion, Dr. Wheeler is there to comfort her. Imagine her shock when this “routine” surgery goes awry and Nancy is left in a coma.

When Susan starts asking questions, the hospital’s usual CYA deflection reaches a whole new level. She’s constantly called into the office of the chief of medicine (Richard Widmark, a real villain’s villain) .

“I certainly don’t want to lose a good surgeon,” he growls, with a menacing smile.

Every place Susan goes, she gets either a run-around or some answers. Even when she learns something, whoever she’s asking flips-out and squeals on her. A terrific scene has her question the cynical, kind of callous pathologists, one of whom is played by a very young Ed Harris.

“Suppose you wanted to put people into a coma,” she asks. “What would you do?”

And where do those patients end up after “our lousy luck” at Boston Memorial has rendered them unrevivable? The Jefferson Institute, where a real rival to Nurse Ratched (Elizabeth Ashley) presides.

“Coma” is about Susan’s empathetic curiosity and dogged determination to find out what’s going on, her lover’s blindness to what’s increasingly obvious to her, and how far people will go to keep the surgeon with the sexy accent from finding them out.

Critchton was a competent director whose greatest contributions here might have been recognizing the hook in Cook’s novel, the plausibility of it all, and in making sure he cast well and hired the right production designer (Albert Brenner, art director or production designer on “Bullitt, “Backdraft,” “2010”).

That image of dangling “vegetables” is just as haunting today as it ever was. Now, it’s iconic.

The film is enough of a watershed moment in cinema to deserve “classic” status, even if it’s a tad mild-mannered (PG rated) and convoluted.

Watching it now, we can see Critchton’s attention to medical detail, which found its fullest flower on TV in his series “ER.”

The suspense is well-handled, here and there, but the shocks and surprises are few. The minute we see that Susan drives an MGB convertible we know there’ll be a moment when it won’t start and she’ll be A) kicking it and B) put in peril.

One of coma patients is a monobrowed smart aleck who would go on to hustle “reverse mortgages” — Tom Selleck.

Critchton’s best directing job remains the Brit film about two 19th century thieves — Sean Connery and Donald Sutherland — out to stage the first “Great Train Robbery.”

But every thriller that uses science and makes informed, somewhat plausible (NOT “Timeline”) fictional speculations about where science might take us owes something to Michael Critchton, the guy who started worrying about AI ahead of the curve, and who will deserve at least some of the credit when we bring a wooly mammoth, a passenger pigeon, a Tasmanian tiger or dodo bird back to life

Rating: PG, violence

Cast: Geneviève Bujold, Michael Douglas, Rip Torn, Elizabeth Ashley, Hari Rhodes and Richard Widmark.

Credits: Scripted and directed by Michael Critchton, based on the novel by Robin Cook. An MGM release now on Amazon, Youtube, Movies! etc.

Running time: 1:53