Well, late as usual, and I see someone already mentioned Starship Troopers…OK, how about Lawnmower Man? Shit.
Fine, I nominate The Running Man. From plot to tone, the movie was not very simular to the book.
Actually, they lifted a lot of the screen story from another erne book, the on whose title is translated as The Weapon of Destruction. his also served as the basis for a Czech film, released in the US under the title The Fabulous World of Jules Verne. It’s interesting to compare the two.
Others have mentioned some candidates for this clumn I would have.
When they started out, the James Bond movies were relatively faithful. They started departing when Fleming died. The very next film afterwards was You Only Live Twice. The screenplay was by Fleming friend (and fantasy writer) Roald Dahl, and has no resemblance to the book at all, except for Tiger Tanaa and his Magic Subway Car. The next film, On Her Majesty’s Secret Service, was almost dad-on the book, but after hat none of the bond films bore an resemblance to the books until For Your Eyes Only,wihch was adapted from the story of that name, the story “Risico”, and a tuch from “Live and Let Die”. The next film, Octopussy, tried to borrow from “Octopussy” and “Property of a Lady”,but its heart wasn’t in it. The Living Daylights took little from the story of that name, but no other Bond film has tried to be faithful to the Book. So the “unfaithful” Bonds are:
**You Only Live Twice
Damonds are Forever[/B (even though they released the novel as a tie-in)
Live and Let Die
The Spy Who Loved Me (actually, Fleming forbade them from filming the novel before he died)
Moonraker
Octopussy
The Living Daylights
On the subject of James Bond… interestingly, in many respects, Timothy Dalton’s “License to Kill” was much closer to Ian Fleming’s novel “Live and Let Die” than the ROger Moore movie “Live and Let Die” was.
This far and no mention of Strange Brew?
Let’s see, how are things different? Rosencrantz and Guildenstern are now named Bob and Doug Mackenzie and they are the leads. Elsinore Castle is now a brewery. Uncle Claude still usurps power, but is mostly the lackey of Brewmeister Smith - I have no idea who he’s supposed to be from the original. Hamlet is now a female lead named Pam.
There’s also the whole hockey-themed stuff which wasn’t in Mr. Shakespeare’s work at all.
That makes a grand total of 2 out of about a dozen people I know (including myself) who are familiar with both versions who don’t think the movie DESTROYED the GN.
Brandon Lee WAS well cast, and did a VERY good job, but the movie removed all the emotion from the book - the muder being random and particularly brutal gave it a lot more effect than the almost incidental ‘business’ it was in the movie.
Also making the kid older (and much more self-sufficient) ruins her scene.
The lead character in the novel “Starship Troopers” is named Juan Rico, not John. His teacher from the book (Dubois, I believe) is combined in the movie with that of his platoon leader, Raczek. Carmencita Ibanez was the character in the book, IIRC, though he may have called her Carmen. Is “cita” a name suffix adding some meaning to a name, anyone?
And Cal, actually the opening sequences of the film “The Living Daylights” are very faithful, but time compressed, to the short story, even including Bond’s tagline to the effect “I scared the living daylights out of her.” Here the short story ended, but the movie kept going.
To those not into Bond, in the short story, Bond and another agent have a young celloist (or similar instrument) under surveillence in Berlin, knowing she is really a sniper out to kill someone or another. Over the course of a couple weeks, Bond becomes infatuated with her, and when she prepares to shoot her victim, Bond shoots her rifle out of her hands instead of killing her as he was ordered to do. He ends by explaining to the other agent that she’ll never try that again as his shot may have broken her wrist (or maybe he shot her in the hand, can’t recall), as well as scaring the living dayights out of her.
The movie compresses this to a day or two (perhaps just one, I don’t recall), but the events play out pretty much as in the story. Bond becomes infatuated, shoots her rifle out of her hands, and offers the same “living daylights” tag.
Wasn’t there a third story used in “For Your Eyes Only”? I seem to remember a short story about motorcycle couriers being killed off, or something like that, that got mixed into a stew with a couple other shorts for one of the later Moore films.
Sir Rhosis
I’m not sure about “cita” but “-ito” for the masculine usage and “-ita” for feminine, is the same in Spanish as “-y” in English.
Mike for example may be called Mikey, as Miguel may be called Miguelito.
From what I hear (I still haven’t come across a copy of the story, dammit) “Total Recall” isn’t much like “We Can Remember it For You Wholesale”. Not surprising, it’s hard to imagine Arnold as the protagonist in a Phillip K. Dick story. (And what’s with Hollywood always fucking with Dick’s much much cooler titles?)
I’ve got one- “Naked Lunch”. Ok, there’s one you could argue is unfilmable. But if you’re going to do it, taking out all the elements of social satire and substituing biography is not a good solution. They should have just dropped the pretense that they were filming the book and called it “William Burroughs”.
Oh yeah, and let me second “The Scarlet Letter” just because what they did to it was so very vile.
The godfather … the movie is only 60 percent of the book
althouhg some could argue that the missing passages dont have anything to do with the book
The johnny fontaine story explains how the family gets in the movie business and vegas in the book johnny wins the academy award and gets his singing voice back
The story of how mike colorene gets his version of luca brasi who in the movie is the cop that shoots barzini in the car is woefully skipped over
now in the first book it explains how vito became don it that part of part 2? ive never got to see it all
another movie that left out is the terminator 2 movie the first and last scenes in the book would of made more sense of the movie ie john connor sends his father back to warn his mother that the second one is coming right before the resistance takes out sky net permantly
and the last scene is where sarah as a old woman is standing on judgment day at the playground she dreams about and nothing happens and says mission accomplished
one last one in the original back to the future book it explains when marty wore his radiation suit woke up his father and told him to take his mother out saying he was darth vader
in the movie all you see is si him slipping on the head phones and waking him up
I know Starship Troopers has been done, but I’m a Heinlein junkie, and I still wanna weigh in here.
MAJOR SPOILERS (Read the novel. Forget the movie (and you will once you get into the book, trust me) and read the novel.)
In the novel …
[ul]
[li]the suits make sense. They have everything from nonlethal gimmicks like grenades that announce they are time bombs to lethal weapons like grenades that are tactical nuclear bombs. The suits themselves are essentially an extra layer of muscle with armor, weapons, and a jump jet strapped on. To paraphrase the novel, you don’t ‘pilot’ a suit, you just wear it. That’s their advantage.[/li][li]we have a good reason for not just nuking the bug planets: Bugs and humans like the same kinds of planets, so ruining bug worlds would limit our colonization opportunities. In fact, fighting for the future of the human race is a main theme of the novel.[/li][li]the scene where the boot camp soldier gets his hand knifed to the wall does not happen, because the novel explained why soldiers would learn archaic methods of fighting. In essence, the novel said there are no dangerous weapons, just dangerous people. And a soldier had better be able to take out a guard armed with everything up to and including tactical nukes (see above) with whatever is on hand.[/li][li]the bugs look completely different. They are actually arachnids (spider-like things), not just big beetles like in the movie. It’s a stylistic point, but those errors get on my nerves.[/li][li]the politics of Earth almost make sense. Heinlein was not a fascist. He was a Libertarian, as The Moon is a Harsh Mistress (and, to a much lesser extent, Podkayne of Mars) show, but he loved experimenting with off-the-wall political ideas. And he did so intelligently. His society in Starship Troopers is based on the military, with corporal punishment given out to people young and old. In fact, parents are punished alongside their delinquent offenders. This gives the novel’s Earth a completely different feel from the Naziesque Earth of the movie. I don’t think anything can justify fascism, but Heinlein created a political thought experiment that comes close.[/li][/ul]
Finally, the novel is amazingly well-written, intelligent, enthralling piece of fiction, whereas the movie is a piece of crap.
And if anyone makes a bad version of Stranger in a Strange Land, I will personally give them a new appreciation of unarmed combat (i.e., combat after they have lost their arms). 
Damn, my two biggies (Dune and Lawnmower Man) are gone already.
How about Clear and Present Danger? They turned John Clarke into a paid assassin and lost three quarters of the plot.
Logan’s Run. They took the skeleton of the premise and the names of the main characters, and then changed everything else.
Some Spanish words form diminutives by taking -ito or -ita, and some take -cito or -cita. (I’m sure there’s a rule, but it escapes me at the moment.)
What? No mention of The Shining??
I am a purist when it comes to adaptations, so I thought that it was frightening how little Stanley Kubrick’s so-called masterpiece had to do with the novel. The biggest flaw being that Jack’s Jack is full-on nuts from the beginning, instead of subtly and slowly decenting into madness, that alone destroys the plot of the novel. Though I’m well aware that I’m in the minority, I vastly prefer the mini-series that came out in 1997. It was true to the bookand I love it. I’m not saying that Kubrick’s movie wasn’t good or scary, but it wasn’t The Shining by Stephen King either.
Bless the Child, on the other hand…not even redeemed by the “good if you don’t care about the book” factor.
My favorite in this category is Everything You Always Wanted To Know About Sex (But Were Afraid To Ask).
The segments with Gene Wilder as a sheep-lover who drinks Woolite, and Woody Allen as a nervous spermazoon, are clasics of comedy.
Thought of another one. The Shining, as directed by Stanley Kubrick. It’s great and all, I loved it, but the movie cannot hold a candle to the book. The similiarties are it’s about a guy going crazy and there are some other moments taken from the book, but the essence is missing, as well as 70-80% of the plot. 
Sometimes you just gotta stick with the original master.
Ah damnit, I just realized someone else thought of it too! Well, I don’t care, I’m not deleting my post.
The same thing happened with The Running Man, though I’m not sure if anyone has mentioned that one, but the fact that they cheer him on the movie is horrible. The book is so depressing because practically no one is rooting for him- at least not the “audience.” I don’t know how the movie ends, but, well…I don’t really care.
Man, it’s hard to make a decent movie out of a Stephen King book.
Part II does explain how Vito came into power.
And Terminator, Terminator 2, and Back to the Future were based on books?
I have to pipe in with Disney’s Tarzan. I hadn’t really wanted to see this movie, but it was at the dollar theater, so my wife and I went to see it.
The first half or so was unbearable, only superficially related to Burroughs’ Tarzan of the Apes. After that though, it went to hell pretty quickly. I wanted to claw my eyeballs out.
GES
I used to love K. Dick books, so I’ve read the book before seeing the movie. Indeed, they have very few in common. But IMO, it’s one case where the movie is vastly superior to the book.
Indeed, apart from the premise (the guy thinks he actually went to Mars), the movie is another story entirely. The short story is…well, very short, and mainly sarcastic. A weird thing is that there’s in the movie a scene which is really similar to the usual Dick plots (when a doctor tell to Schwartzeneger that actually he isn’t on Mars but still dreaming while they’re are attempting to reanimate him…Dick’s characters are quite always unsure about the reality of the world they live in), and doesn’t appear in the short story. I was really surprised to discover that it wasn’t Dick’s idea.