In The Post-Birthday World, Lionel Shriver explores the question of "what if?" Irina and Lawrence, two Americans living in London, have been in a committed relationship for several years, and have a yearly tradition of spending the evening with their friend/acquaintance Ramsey on his birthday. During the year when the novel begins, Irina ends up alone at dinner with Ramsey, and finds herself tempted to kiss him. From this chapter forward, the novel splits in two, with the chapters alternating between what things would be like if Irina did in fact give into temptation, and what things would be like if she didn't.
The novel is told from Irina's perspective, so it was very interesting to me how I was made to feel about the different men in her life based on which part of the narrative is occuring. I really enjoyed the novel, and the way Lionel Shriver explored the ways things would develop based on this choice. She takes the reader through many parallel scenes, leading the reader to believe that many things would have occurred similarly yet rather differently (for example, Ramsey attends a certain snooker tournament in both alternatives, Irina ends up writing a children's story rather than just illustrating in both relationships). Neither man is exactly perfect: Ramsey is temperamental, egotistical and starts many embarassing arguments, while Lawrence is arrogant and domineering. Still I preferred her life with Ramsey which was a bit of surprise since that's the one that involved her cheating. However, one thing that was good about that situation is that Irina didn't sneak around behind Lawrence's back for an extended period of time, and quickly made up her mind to leave him. In fact, I really liked Lawrence as the man she left, and felt very sympathetic for him, but strongly disliked his smugness when they were in a relationship together. I think one reason may be that Lawrence was a bit better at being diplomatic but in some cases this meant he sided against Irina while Ramsey would start arguments with others to defend her.
The chapter that closes the novel closes the loop again, and can be read as the ending to either story line. The ending is the same but the journey and the subtext of the scene are completely different based on the previous chapters. I liked that Shriver brought the stories back together the way she did, since it does support the saying, "it's not the ending that matters, it's the journey." It's one of the reasons I have no problems reading books, watching movies or shows even when I know what the ending will be. I really liked this novel, and how well Shriver developed the characters. I also thought it was easy to believe how different Lawrence would be from one narrative to the other since Irina was treating him differently - he acts considerate in response to her odd behavior, but completely takes her for granted when she feels appreciative of their relationship.