The guest list for Gatsby's party supports Gatsby's efforts to support his delusion of being one of the beautiful and important people in the New York social society of his time. Fitzgerald populated the party with individuals representing all the interest groups and influential parties and varied activities that were present in the United States at that time.
Guests came from East Egg, the location of the old money and long-established social importance. Guests came from West Egg, newer members of the social elite. Others came from New York City proper and from other locations and backgrounds. The common factor among all the guests was that they "accepted Gatsby's hospitality and paid him the subtle tribute of knowing nothing whatever about him." Knowledge of their host wasn't as important as being seen among all those other recognizable (for reasons reputable or not) people.
In Chapter 3, Nick describes in detail one of Gatsby's lavish parties. Fitzgerald tediously takes the time to list the party guests to demonstrate the eclectic nature of the guests who visit his home. They range from Old Money society folks to the newly wealthy to entertainers. Most of them have one thing in common--they care nothing about their host, and they practice the behavior of those who attend "amusement parks." While Nick is amused and perplexed by the raucous actions and conversation of the guests, he is also critical. He realizes that the party-goers simply use Gatsby, and this foreshadows how Tom and Daisy--future party guests--will treat the host.
Fitzgerald's listing of the names of the characters also illustrates the mingling of society during the 20s. While the Old Money folks felt superior to the New Money people, many of them still "swam in the same circles" when it came to entertainment and leisure.
The reason that the author describes the party guests is the style of the writer. The story is told from the perspective of Nick Carraway, who is the narrator. He sees the details of the story through the different characters, so we learn about them according to how Nick feels about them.
Each of the guests has a different identity that helps the reader understand the morality of the time, the culture clash between the Eastern rich and the people from the Midwest. Gatsby's parties are symbolic of achieving the American dream.
Also, the guests are identified for the purpose of allowing the reader to visualize the lifestyle and setting of the book. This period in history, just after World War I and the Great Spanish Flu Epidemic which killed between 40 and 50 million people, depicts a time when people wanted to forget about war and disease and just have lavish parties.
At the beginning of Chapter 3, Nick Carraway explains how he once recorded the names of Gatsby’s party guests on “the empty spaces of a time-table”. At first glance, the list seems rather boring, redundant and meaningless. However, when you consider the guest list in relation to thematic ideas of wealth, social status and corruption, it might begin to make more sense.
Clearly, the guests represent the wealthy and respectable class since Fitzgerald drops brief hints about several of the guests’ educational or occupational backgrounds. Interestingly, though, nearly every time Fitzgerald goes into any length to describe a particular guest, the description reveals a negative detail (“drowned last summer”, “flipped up their noses”, “hair turned…cotton-white”, “had a fight with a bum”, et al). These pessimistic descriptions, then, underscore Fitzgerald’s dismay with the corrupt nature of the wealthy and, as a result, help prove that the American Dream has become distorted.
Most likely to show us the wide variety of guests that came to Gatsby's house. Other than having money, there seems to be no real rhyme or reason as to the guests that are invited (or just show up). We learn later that Gatsby was very open with his invitations to wealthy people in the hopes that Daisy would end up coming to a party. This was one example that we receive as readers that shows us the extent Gatsby was willing to go to in order to find Daisy again.
The listing of the guests shows just how shallow that set of people can be: the list is long to show the pervasiveness of this attitude. Fitzgerald describes the party-goers as "moths coming to the flame."
Fitzgerald writes that "introductions (were) forgotten on the spot and enthusiastic meetings (happened) between women who never knew each other's names (Ch II).
It is not surprising, then, that the guests have no real relationship with Gatsby, nor do they desire one. His parties were the current hip spot. Today we would call these people the "glitterati." But as the novel proves, all that glitters is not gold.