Quick summary: (too) long, interesting, enjoyable (as long as you skip stuff), but ultimately unacceptable.
A famous work; here's its wiki entry. I'm not going to bother attack its many faults too strongly, because they are too obvious. If you want to read someone disliking it, try CIP. As a token: the many long dense passages of philosophy - Rand's "Objectivism" - that lard the book get increasingly boring as they repeat. This culminates in John Galt's 70-page 2-3 hour speech on the radio, which is more like something you'd get in Cuba or communist Russia than in the cold West. Some of the characters - the dashing pirate - are laughably implausible. But enough criticism (errm, I won't keep to that. Sorry).
The image the book conjures up - of a fading darkening America crumbling under the weight of an unproductive, uncomprehending and eventually almost unwittingly hostile bureaucracy or parasitic class is well done, and will strike a chord with anyone who actually makes things. Those who work for the govt may be less impressed (token: I find her hatred of all govt funded research ridiculous. But hey, I was a govt-funded scientist for years). But Rand's solution - that all the able folk withdraw their labour and their physical selves and rebuild society in a quiet corner before, presumably, walking into the territory emptied by starvation, cold and strife is hard to see as acceptable. As an aside, at the present day, the central core of the hardened capitalist struggling to keep a railroad - yes, a railroad - going seems very quaint and 50s.
A veil is drawn over most of the deaths, but she helpfully provides one example: the wood burning transcontinental sleeper train taken through the long tunnel. It gets stuck inside, and everyone dies. Rand is at pains to set up the incident as an example of bureaucratic stubbornness and buck-passing (someone at the top decrees the train must get through, but all the way down officials area at pains to ensure that the disastrous orders they give can't be traced back to them) and does her best to make it seem as though all the passengers deserve death; but they don't.
You'll have to forgive me some vagueness here: I started reading the book on the way back from the Amsterdam marathon last October, and finished it a few weeks later, so my memory is fading.
And yet the two key intermingled ideas are worth thinking about: that there is a parasitic class leaching off the productive, and that this class is actively harmful (in Darwinian terms, they are bad parasites). In the book, as things go wrong, the parasites use fear of the problems to gain more power and control, and they use that power to throw patronage at their friends, but they also make genuine (to them; at least the book doesn't try to say otherwise) attempts to fix things, but because they are incompetent things just get worse. The attempt-to-fix-but-fail stuff is very true to life for anyone watching politics ever. The Tobin Tax propsed for the EU is a possible example. The stupid carbon trading schemes are another. These are examples where pols motivated by - well, we cant see into their minds, so we have to guess - a combination of shallow and wishful thinking, carelessness and stupidity, and a desire for patronage, act to make the world worse.
Since I've mentioned Darwin I need to complete the thought: which is, that parasites are universal, unless you make great efforts to remove them. Rand's idea is for a parasite-free society. Like many others she has no patience for fixing the old - its a tired toy, she will throw it away and make a new shiny one; lives don't matter to her; or at least, not the lives of small people. Inevitably, her new world would acquire parasites, but that's for the future. Our world is infested by parasites; what keeps them down is partly Democracy and blah; partly that anywhere that becomes too uncompetitive gets out-competed. That's not a careful analysis, but what I mean is that we accept a balance as we must: as long as society functions, and produces enough wealth for all or most, we tolerate some parasites. And at least at the moment it is working: the share captured by the unproductive isn't too high. In Atlas Shrugged Rand has had to produce a less capable society that succumbs to the weight of parasites - though even there it isn't really clear that it would do, if it wasn't for the "strike". Rand's various protagonists have decided - amongst themselves - that all the invisible deaths are worth it, to them. It is a very individualistic philosophy, and to support its plausibility all the lead characters are implausibly capable.
If you agree that Rand's apparent solution - restrict, retreat and rebuild - isn't very plausible, what lesson does the book teach? Just, resistance to stupid bureaucracy I suppose. Put like that, its not profound. And I do sense that many of the book's admirers are motivated more by some savage uncomprehending hatred of The System rather than by a desire, themselves, to try to build something better. Nonetheless there is something there.
[Edited to add: if I'm not mis-remembering, another important element to Rand was the coercive power of the State: its structure and authority is based ultimately on force. She doesn't like this; it doesn't fit with her individualistic world. Nonetheless in the book the state is rather uncoercive: only at the end is there a carefully contrived torture-John-Galt scene, which is inserted only to fulfil her own prophecy, that the state will ultimately resort to force. In this, I'm firmly with Thomas Hobbes and against Rand: without the Civil Sword, no compacts and hence no civil society is possible. Rand's insistence otherwise places her with the hippies and flower children, who she would despise.]
* Ayn Rand’s 1957 philosophical novel Atlas Shrugged may not be a literary masterpiece or the last word in political theory, but it does hold some lessons - even Pierre Lemieux, good libertarian that he is, can't bring himself to be very complimentary.