What is the meaning of "The Unpassing" in the novel, The Unpassing?

Throughout the novel, catastrophes can sometimes appear to reverse themselves, a theme which is introduced in the novel's title. "The Unpassing" refers to the idea of un-happening or un-dying, to use two common synonyms for "pass" (to happen or, euphemistically, to die). The novel opens with Gavin's mother seemingly passing, but then un-passing, as she stands up and berates the children for doing nothing to save her. By "testing" them through her pretend death, the mother inadvertently teaches Gavin "reversal": "Things that had been splintered could be intact again" (8). This opening scene makes the irreversible deaths — the Challenger disaster and Ruby's sickness — that occur in this chapter more incomprehensible to Gavin.

Unpassing also occurs with travel and distance, as in the case of the family's migration from Taiwan and the father's separation from the family. Although Gavin returns to Taiwan, physically undoing the distance his father caused by choosing to immigrate to the U.S., he never fits in and realizes that the damage caused by his disconnection from home is irreversible. Earlier, when the family moves to Seattle, Gavin and Natty watch the television coverage of the Exxon Valdez oil spill and see a person they believe to be their father on the screen. In both cases, the physical distance and emotional disconnection is impossible to completely undo, but family members like Gavin's father and his aunt re-enter Gavin's life in surprising ways after a seemingly final disconnection.