This is a common technique in storytelling called flashback (analepsis). The use of this technique often adds a sense of mystery to the story. The use of flashback allows the author of the story to interrupt a storyline by taking the reader back in time to a point that helps define the character, setting or plot line. By revealing flashback clues throughout the piece the reader can catch a sense of the struggle that had placed the lead character in such a predicament.

This approach can take an average story and make it much more interesting. By cutting to previous events, the reader becomes more interested in the mystery of the storyline.

Flashbacks work very well for a dramatic storyline because it provides one of the best means of bringing the reader into the life of your character on an emotional level. The reason this seems to happen is because it allows you to enter the thoughts of the character and experience the pain or joy of past experience. This is something that is much more difficult in a story operating on only a forward timeline.

It is true that flashbacks can make the majority of the story confusing, but the concept is a bit like putting a puzzle together - you're not really sure where each piece fits or what the picture really looks like until the very end. Therein lies the payoff.

The flashback writing technique can also be called back-story, although this technique generally refers to a fully developed story that is typically viewed as a prequel. One of the most widely heralded uses of this technique is Star Wars where three full stories were developed before George Lucas ever filmed his first movie in 1976.

A similar technique to flashback is flashforward (prolepsis). In this scenario, the main character is in a time past and the flashforward shows a bit of the fate that awaits them as the story unfolds. Horror writing often used flashforward as a means of prophesying the fate of their main character.

Flashback remains just one tool in a writer's arsenal to allow the story to become something epic.