I had no idea Rossen worked on this movie- but he's the only writer credited. And from reading it, this felt similar to the movie - although it's been a while since I saw it. There was a bit where Curtin (the Tim Holt character) does a big speech about Mexicans after someone refers to them as bloodthirsty and Curtin points out that you'd be bloodthirsty too if you'd had to suffer from years of abuse etc etc - the sort of good old progressive attitudes that commies would put in scripts (not a criticism!)
Maybe it's simply a very faithful version of a very filmable novel - I'll leave it to an academic to do a proper comparative analysis.
I was a tad underwhelmed by this film when I first saw it - I seem to say that a lot about John Huston movies - but enjoyed reading the script. The theme is very universal - down and outers going prospecting for gold, finding it... then realising once they do their problems have only just begun. How do they divide it up between them? What to do when another American, Cody, stumbles upon their campsite and figures it out - kill him or make him part of the partnership? What to do when some bandits come along - bluff or fight? At what point do they leave? What to do when some Indians demand their main prospector go with them?
For a film famous as a work on paranoia, the characters act rationally most of the time - Curtin, the everyman, is pretty much consistently normal and rational - he saves Dobbs' life, always tries to do the right thing, and at the end goes off to find Cody's widow. Howard,the grizzled prospector, is so wise and smart, not just about gold mining but human nature, that you wonder how he wound up in a flop house at the beginning - he spots the gold site, helps dig it, is brave and smart, predicts how people are going to act... Even Dobbs is normal most of the time - he's a bit tetchy but it's only at the end he goes ga-ga.
The film is a bit racist towards Mexicans - the bulk of them are corrupt and ruthless. The Indians are naive. The bandits are genuinely scary (and they should be, lopping off Dobbs' head) - though it should be said the police are quite efficient (though ruthless too).
A very satisfying look at greed with some suspenseful scenes and one very juicy role (Dobbs).