Pulitzer prize-winning author Michael Cunningham's Specimen Days is overwhelming in the most positive sense, not only in its various temporal contexts (the first section of the novel takes place during the Industrial Revolution, the second in present day, and the third is pitched far into the future), but also in the opulence of the language. It is appropriate that Walt Whitman's verse, and even Whitman himself, appear repeatedly in this story, because there is a thematic concordance between what Cunningham seems to pursue here, and what Whitman offers, according to Rita Dunn, an NYU professor who appears in the second section of the novel. " '[Whitman] didn't just celebrate himself,' " Rita says. " ÔHe celebrated everybody and everything.' " In this scene, Whitman's voice is a small part of a larger mystery; Rita is addressing Cat Martin, a psychologist who is trying to decipher why a group of children, threatening those around them with random violence, keep offering bits of Whitman's verse instead of explanations.

Each of the three sections is haunted by Whitman. In the first, "In the Machine," Lucas cannot control his speech, and recites Whitman's poetry without necessarily desiring it; he calls this "speak[ing] as the book." In the final section, "Like Beauty," a designed being with a human appearance named Simon has a "poetry chip" that causes him to speak Whitman's words. Despite the range of conflicts and landscapes in each of these sections, the characters have a similar consciousness. Lucas, Cat, and Simon, each surrounded by suffering, danger, and death, have rhapsodic encounters with sensory pleasure. Lucas imagines that "Broadway would be [his] heaven," drawn in by "Ladies in dresses the color of pigeons' breasts, the color of rain[...] Red curtains billowed in the windows of the hotels, under a sky going a deeper red with the night." There are many such moments of rich description, and Cunningham frequently places them on the cusp of serious danger. The "laughter" described as "high, crystalline, songlike" belongs to a woman who calls herself Walt Whitman and commands the children under her care to commit violent crimes. Cat Martin, who ultimately chooses to shelter one of these children, understands the danger she has chosen for herself, but she is inspired to notice what has caused the child to become "enraptured." Cunningham writes, "Although the field of cattails was interrupted periodically by asphalt tundras full of empty delivery trucks, and was studded with utility poles and smokestacks, Cat had to admit that there was something...wild about it, if not exactly beautiful."

In "Like Beauty," Simon struggles with the capacity to appreciate the world he sees around him. He tells Catareen, a companion who is from the planet Nadia, "[...] I understand about beauty, I get the concept, I know what qualifies, but I don't feel it." This notion of "feeling" beauty exists as the connector between the three sections of the novel, and in some ways this continuity, and the quality of the writing, is more effective than the fact that the main characters share the same names, or versions of them, in each section (Catherine, Cat, and Catareen, for instance, in each of the three sections, respectively). Nonetheless, Cunningham succeeds in joining the experiences of three narrators from different places and bodies - Lucas, the Irish immigrant in the Industrial Revolution; Cat, a black psychologist in present-day; and Simon, who is not human at all - through the willingness to linger on the small details that create what is pleasurable.