In the world of The Lunar Chronicles, ID chips are an integral part of people’s everyday lives. They function not only as personal identification but also as a means of buying things, keeping in touch with family, and being tracked in case of an emergency. However, throughout the novel, ID chips become complicated symbols, and as Cinder learns, ID chips represent a person’s sense of belonging in Earthen society.

In the first novel of The Lunar Chronicles, Cinder watches in horror as the medical androids in the New Beijing quarantines try to cut out her deceased stepsister Peony’s ID chip. Cinder panics and steals the chip, and she isn’t sure why anyone would order an ID chip to be cut out of a dead person. Scarlet provides a partial answer: In Chapter 30, Master Jael tells Wolf that they’ve “just received [a] shipment of ID chips from the Paris quarantines” (312), all of which were presumably stolen from the bodies of letumosis victims. Jael then orders Wolf to “take [the chips] down for wiping and reprogramming” so they will be “ready for the new recruits [he] expect[s] to arrive” (312) the next morning. The Lunars are stealing ID chips to fabricate new identities for the Lunar soldiers they are hiding on Earth so that they can pass themselves off as regular human Earthens.