In The Great Gatsby Fitzgerald offers up commentary on a variety of themes — justice, power, greed, betrayal, the American dream, and so on. Of all the themes, perhaps none is more well developed than that of social stratification. The Great Gatsby is regarded as a brilliant piece of social commentary, offering a vivid peek into American life in the 1920s. Fitzgerald carefully sets up his novel into distinct groups but, in the end, each group has its own problems to contend with, leaving a powerful reminder of what a precarious place the world really is. By creating distinct social classes — old money, new money, and no money — Fitzgerald sends strong messages about the elitism running throughout every strata of society.
The first and most obvious group Fitzgerald attacks is, of course, the rich. However, for Fitzgerald (and certainly his characters), placing the rich all in one group together would be a great mistake. For many of those of modest means, the rich seem to be unified by their money. However, Fitzgerald reveals this is not the case. In The Great Gatsby, Fitzgerald presents two distinct types of wealthy people. First, there are people like the Buchanans and Jordan Baker who were born into wealth. Their families have had money for many generations, hence they are "old money." As portrayed in the novel, the "old money" people don't have to work (they rarely, if ever, even speak about business arrangements) and they spend their time amusing themselves with whatever takes their fancy. Daisy, Tom, Jordan, and the distinct social class they represent are perhaps the story's most elitist group, imposing distinctions on the other people of wealth (like Gatsby) based not so much on how much money one has, but where that money came from and when it was acquired. For the "old money" people, the fact that Gatsby (and countless other people like him in the 1920s) has only just recently acquired his money is reason enough to dislike him. In their way of thinking, he can't possibly have the same refinement, sensibility, and taste they have. Not only does he work for a living, but he comes from a low-class background which, in their opinion, means he cannot possibly be like them.
In many ways, the social elite are right. The "new money" people cannot be like them, and in many ways that works in their favor — those in society's highest echelon are not nice people at all. They are judgmental and superficial, failing to look at the essence of the people around them (and themselves, too). Instead, they live their lives in such a way as to perpetuate their sense of superiority — however unrealistic that may be. The people with newly acquired wealth, though, aren't necessarily much better. Think of Gatsby's partygoers. They attend his parties, drink his liquor, and eat his food, never once taking the time to even meet their host (nor do they even bother to wait for an invitation, they just show up). When Gatsby dies, all the people who frequented his house every week mysteriously became busy elsewhere, abandoning Gatsby when he could no longer do anything for them. One would like to think the newly wealthy would be more sensitive to the world around them — after all, it was only recently they were without money and most doors were closed to them. As Fitzgerald shows, however, their concerns are largely living for the moment, steeped in partying and other forms of excess.
Just as he did with people of money, Fitzgerald uses the people with no money to convey a strong message. Nick, although he comes from a family with a bit of wealth, doesn't have nearly the capital of Gatsby or Tom. In the end, though, he shows himself to be an honorable and principled man, which is more than Tom exhibits. Myrtle, though, is another story. She comes from the middle class at best. She is trapped, as are so many others, in the valley of ashes, and spends her days trying to make it out. In fact, her desire to move up the social hierarchy leads her to her affair with Tom and she is decidedly pleased with the arrangement.
Because of the misery pervading her life, Myrtle has distanced herself from her moral obligations and has no difficulty cheating on her husband when it means that she gets to lead the lifestyle she wants, if only for a little while. What she doesn't realize, however, is that Tom and his friends will never accept her into their circle. (Notice how Tom has a pattern of picking lower-class women to sleep with. For him, their powerlessness makes his own position that much more superior. In a strange way, being with women who aspire to his class makes him feel better about himself and allows him to perpetuate the illusion that he is a good and important man.) Myrtle is no more than a toy to Tom and to those he represents.
Fitzgerald has a keen eye and in The Great Gatsby presents a harsh picture of the world he sees around him. The 1920s marked a time of great post-war economic growth, and Fitzgerald captures the frenzy of the society well. Although, of course, Fitzgerald could have no way of foreseeing the stock market crash of 1929, the world he presents in The Great Gatsby seems clearly to be headed for disaster. They have assumed skewed worldviews, mistakenly believing their survival lies in stratification and reinforcing social boundaries. They erroneously place their faith in superficial external means (such as money and materialism), while neglecting to cultivate the compassion and sensitivity that, in fact, separate humans from the animals.