The Tristero is a privatized clandestine postal delivery service, the existence of which Oedipa uncovers during the course of her investigation. Throughout this investigation, the mystery surrounding the Tristero comes to symbolize the existence of a secret world hidden in plain sight. Once Oedipa learns about the society's muted-post-horn symbols, she sees the image everywhere. She sees the acronym W.A.S.T.E. scrawled on everything from bathroom stalls to garbage cans, the latter of which turns out to be a mailbox system for the Tristero organization. Oedipa never thought about the existence of such an organization, claiming she always used "the US Mail because [she] was never taught any different" (84). After learning about Tristero, however, she cannot un-see the truth about the world around her. In this sense, the Tristero represents the power of the hidden world. Once Oedipa has learned about the Tristero, she begins to understand how little she comprehends about reality and existence. Her investigation morphs into a desire to learn more about Tristero, an investigation that broadly symbolizes the desire to learn more about the secret machinations of the world, which are hidden in plain sight.

While talking about the importance of the secret mail-delivery networks, Bortz claims that "whoever could control the lines of communication, among all these princes, would control them" (126).