Frank Norris was an American naturalistic writer. His novel McTeague exists as one of the best American naturalistic novels of the movement. Much of the text can be scrutinized through this lens.

One important quote can be taken from the opening of the novel: "It was Sunday, and, according to his custom on that day, McTeague took his dinner at two in the afternoon at the car conductors' coffee-joint on Polk Street." This quote illustrates the daily rituals typical of the protagonist. McTeague, or Mac, is shown to be set in his ways. This illuminates the naturalistic aspect of a person's nature—the behaviors expected of a person. Naturalism illustrates the power of nature over all else. In the end, the nature of the world and people, in general, does not change. This quote illustrates Mac's consistent nature that one expects to come throughout the novel.

Another quote which speaks to the naturalistic nature of the novel is as follows: "McTeague's mind was as his body, heavy, slow to act, sluggish. Yet there was nothing vicious about the man. Altogether he suggested the draught horse, immensely strong, stupid, docile, obedient." This quote provides readers with a direct characterization, as opposed to an indirect characterization. (A direct characterization tells readers exactly how a character is or looks. An indirect characterization requires readers to infer who a character is, both physically and internally.) Here, this quote depicts both Mac's physical appearance and his character. The metaphor used, as Norris compares Mac to a horse, illuminates the naturalistic aspects of the novel almost immediately and gives the reader a visual image to compare to Mac.

One quote that speaks to the theme of greed in the novel is spoken by Trina, Mac's wife. "We're not going to touch a penny of my five thousand nor a penny of that little money I managed to save—that seventy-five." Mac is described as one who does not struggle financially prior to marrying Trina, and he does seem to be the type of man who knows the real value of a dollar. Trina, on the other hand, allows money to rule her life. After winning the lottery, a sum of five thousand dollars, she becomes overly protective of the winnings. Although they could live a decent life with the money, she refuses to touch the money or allow Mac to touch the money. Greed, one of the themes, becomes evident from the fights that are interspersed throughout the novel following the winning of the money. Trina holds the money from Mac and threatens to leave him without her or the money. Over the course of the novel, money becomes one of the main reasons behind the end of both Mac and Trina.

A quote from later in the novel shows just how much money means to Trina: "'Ah, the dear money, the dear money,' she would whisper. 'I love you so! All mine, every penny of it. No one shall ever, ever get you. How I've worked for you! How I've slaved and saved for you! And I'm going to get more; I'm going to get more, more, more; a little every day.'" This quote, more than any other, shows the intense "relationship" Trina has with her money. She treats the money as if it were a child, one she nurtured and bore from her own womb. Additionally, although she has a good sum of money, she is not happy. She wants more. This tells readers that she will never be happy with any sum of money. It will never be enough.

Perhaps the most important quote, although it is simplistic, is spoken by Marcus (a friend of Mac's). At the end of the novel, Mac leaves Trina, steals her money, and heads to Death Valley to search for gold. Marcus finds him and asks where the money is. At one point, both men realize the dire predicament they are in, which is best voiced by Marcus: "We're dead men." Personified as death, "money" comes for them. Marcus ends up being shot by Mac over the money. Unfortunately for Mac, he has been handcuffed to Marcus, and death for him is inevitable. The novel ends with Mac realizing his circumstances—death will come for him as well.

Essentially, the novel's themes (and much of the dialogue) circulate around the idea of money not being enough to provide happiness in the world. Trina's death at Mac's hands is because of money. Marcus's death is because of money. In the end, Mac will also die because of money. These quotes illuminate the importance of how money can be seen as the root of all evil.