O'Brien uses an interesting technique that moves through time, giving us clues about the characters, but never enough information to know exactly who did what at any one time in the novel ... including the ending. He introduces us to characters in much the same way we find out about the people we live with. We never sit down with someone and query their life story. We find out bits and pieces about people, often the most trivial with the really significant information evolving only through time. O'Brien wanders through time, offering possible interpretations (which can be confusing since we often forget that much of what happens in those chapters is conjecture and not "fact.") For instance, we know that John and Kathy's lives are a disaster, but we don't know why. We find out that he lost an election that he was leading, but we have no idea why. Bits and pieces of evidence from different time periods surface during the evidence chapters, not only from John's life span, but from prior periods in history. The reader gets a sense of putting the characters' lives together as the pieces are presented ... the author provides the information, but we assemble the "pieces." I don't know if this would work for other novels, but I think O'Brien did an interesting job with it in this novel.