Typical of many stories that deal with themes of psychological trauma, Going After Cacciato contains distinct ambiguities concerning the nature and order of events that occur. The chronology is nonlinear for most of the book.
The main idea of the story is, by O'Brien's estimation, that being a soldier in Vietnam for the standard tour of duty entails constant walking; if one were to put all the walking in a straight line, one would end up in Paris, where Cacciato is going.
Cacciato is always portrayed as self-sufficient and happy. It is Cacciato, who is pursued throughout the imagined story of the book. The final pages feature the juxtaposition of two statements, by Sarkin Aung Wan and Paul Berlin, which contrast the early American view (think Emerson and Thoreau) of independence and happiness against the modern view of obligations placed on the individual to conform to society. The obligations lead to complicity in atrocities. Cacciato marches to the beat of a different drum, and is freer and happier in a cavalier, ignorant kind of way. His actions are sometimes portrayed as those of a man who is not particularly bright or gifted, but who is sunnily untroubled by the larger questions of the war itself.
Paul Berlin, the main character, is a frustrated soldier, who during the entire novel focuses on every minor detail he encounters.
In the chapter "Tunneling Toward Paris", the characters escape the endless tunnels by "falling out" just as they fell in; this allusion to Alice In Wonderland helps to reveal the story as surrealistic fiction. This surrealism also appears earlier in the novel, when Cacciato flies off a mountain.