Racism is the central subject of "Telephone Conversation." In the poem, a black guy attempts to finalize a housing agreement over the phone with a landlady. He wants to tell the landlady he's black, and a crazy debate develops over how dark his complexion is. The guy ends up not buying the apartment because of this disagreement. Darkness is also an important theme in the poem. The black man calls himself "a shadow of a shade" and says that everyone thinks he's "about as black as any other white man." Finally, racism is what brings all these different ideas together in the first place. It's the reason this conversation takes place on the phone; it's too dangerous for them to meet face-to-face. In conclusion, the main theme of "Telephone Conversation" by Carl Sandburg is racism. This one idea connects all the different parts of the poem together.