Most stories take place in chronological order: They have a beginning, a middle, and an end. With flashbacks, authors can start a tale at its most exciting moment, then flash back to the past to explain how that moment arose. Writers also can tell a story in the order that best explains the plot points or that creates a maximum amount of drama and tension.

With “All You Zombies—,” the author must explain how a time traveler manipulates events, out of order, to protect the overall timeline. This thought problem is hard enough to follow without some help. The author therefore begins near the end, when the time agent, acting as a bartender, meets his younger self in a bar. Their meeting serves as a frame story—a story that contains another story—in which the two men talk about the past.

The younger self relates his life story up to that point, whereupon the bartender escorts him, via time machine, to his own past to see and fully understand what has happened to him. This inspires the younger self to join the Temporal Bureau and become the time agent who goes back in time to make sure he does join the Time Bureau and thereby safely complete his own history.