I've never seen this movie, so I guess it's a good thing this here site is dedicated to books and not films. Before reading this, I knew that this was a classic movie that had something to do with a valuable bird statuette, and that's about it. Now having read the story, I can understand why it's lauded with praise. Well, actually I'm making an assumption here. It seems that every caricature found in typical early 20th century detective movies and stories have a foundation in this tale. Since it's so typical, I won't spend time expounding upon most of it. 
 Here are a couple of things I found a bit surprising, though. Sam Spade is a straight-up dog. Within the first few pages, it's clear he's had sex with at least three women in the story, and I became afraid I would get chlamydia or something just from reading it. He was just fine with his partner getting murdered. (I don't consider that a spoiler since it happens by page nine). He's fine breaking promises, screwing people over, and beating the hell out of anybody to get his end result. And while I reckon that's what you want in a good private dick, it certainly doesn't make him any kind of a hero in my book. There really is no hero here; everyone involved is a contemptible louse and a weasel. It's kind of hard to care about their fates when that's what you're working with. 
 I suppose there are fun themes in here, but I'm not sure. One character is clearly gay, and it's insinuated that a couple others might be as well, though it's not as blatant. I was surprised that this was touched upon at all in a novel from 1929, but less surprising is the fact that super straightwad Sam Spade spends half the time beating up on all the faggots. I don't think he's beating them up just because they're gay. They are the antagonists, after all, and did pull guns on him. (And by "gun," I mean an actual firearm, not a penis, just in case your filthy mind was wondering. If not, then my filthy has mind has done that work for you). Moving on... 
 I was actually supposed to read this in college in some literature appreciation course, but I didn't. The following semester I was on academic suspension, but that's neither here nor there. I'm not sure why this book was included in the curriculum (along with A Farewell to Arms, Women in Love, All the King's Men, and possibly a couple of others), but I would probably know why it was included if I had paid attention in class... which would've been easier had I attended class. At any rate, I'm now sorry I didn't learn what the big deal was. I hate figuring that stuff out for myself. Nine times out of 10, I don't really care even after I find out about it, but I still always want to know so I can decide whether or not I should care. So, there is probably fun hidden thematic stuff in here for people who like that kind of thing, and such people should scope it out. 
 Hammett's writing style is a departure from my usual fare. He employs laconic restraint when I normally prefer effusive excess (if it's done properly). It's very much in-your-face, however that works well for this kind of story. Some stuff is oversimplified, and like I mentioned earlier, very caricatured. The story keeps moving right along, and I suppose that's what one should want in an action/adventure tale. I enjoyed the hard-boiled language. I didn't even know what hard-boiled was until I looked it up a couple of days ago. Most of it I could follow without having to look up anything, but just what in the hell was I supposed to make of this? 
 "...I don't know how come he left that shelter, but they got him once in New York for knocking over a row of stuss-games - his twist turned him up - and he was in a year before Fallon got him sprung. A couple of years later he did a short hitch in Joliet for pistol whipping another twist that had given him the needle... This Thursby was Dixie's bodyguard and he took the run-out with him when Dixie got in wrong with the rest of the boys..." 
 I'm afraid I had to look up a few things when I got to that paragraph. Luckily I knew the term "heater" and a couple of others which are mentioned elsewhere in the book from a Star Trek episode: "A Piece of the Action." Who said you can't get anything useful from corny old TV shows? 
 Anyway, if what I've mentioned above is your bag, I give this a recommendation. I plan to check out a few more detective novels myself, but I don't think it will become a preferred genre.