“He holds him with his skinny hand,
'There was a ship,' quoth he.”

An elderly man corners a guest at a wedding and enthralls him with a strange tale. In the poem “The Rime of the Ancient Mariner,” the scene with the Mariner and the guest is a framing device. It “frames” the poem at the beginning and again at the end. Think of a framing device as a passageway to the main narrative. Framing devices are also called  “bookends.” They appear in fiction, nonfiction, poetry, plays, television, and films.

Writers often use framing devices as a contrast to the main narrative in format, style, or tone. The most common type of framing device is the flashback, in which the narrator or character tells the story that makes up the rest of the work. Framing devices can also be:

As with any literary device, writers should have a solid reason for framing a story. Framing devices can set up an unreliable narrator, create suspense or mystery, or counter readers’ likely objections to the story or reactions to a character. A framing device can also illustrate a shift in perspective due to time passing or how much a character has (or hasn’t) changed because of the events in the story. Think about how the framing devices in the book (and movie) The Princess Bride or the television show How I Met Your Mother build on and inform the rest of the narrative.

When the Mariner finishes his story, we return to the wedding celebration, where the guest has been shaken by what he's heard. 

“He went like one that hath been stunned,
And is of sense forlorn:
A sadder and a wiser man,
He rose the morrow morn.”

Sometimes, the events of the main story resonate, changing not only the protagonist but the characters in the framing device as well.

Imagine darkness, and then a flashback appears like a lightning strike to briefly illuminate the narrative terrain.

A flashback, according to Syd Field, noted author of books about screenplay writing, “is a technique that bridges time, place, and action to reveal information about the character or move the story forward.” Contrary to its name, the literary device does more than just look back; writers can flash forward to the future or laterally to other present realities as well. Flashbacks show up in films, television, plays, fiction, and nonfiction.

Flashbacks are an engaging way to impart information the audience needs. Sometimes exposition in prose or dialogue feels clunky or unnatural or slows the story. Always have a solid reason to use a flashback. Examples of good uses for flashbacks include:

As with other literary devices, don’t overuse flashbacks. Some writers point out that flashbacks suffer because they are not immediate; the outcome has already been determined. I disagree—I find flashbacks fascinating when done well because they provide missing puzzle pieces to the character or the plot. Still, if you find yourself returning to the past often to show what happened, consider whether it’s better to place the entire story in that timeframe instead.

Just as you need a solid reason for using a flashback, you also need a solid reason for where to place it in the narrative. Arbitrary placement of flashbacks may confuse the audience. In general, place them as late in the narrative as you can, at the last possible moment before the audience needs that information to make sense of what comes next. Place it too early, and you kill the suspense and momentum. Tie the flashback to something the character feels at a given moment. For example, imagine your protagonist lying on the ground, bleeding. A flashback could tie to one of many triggers, including: a memory of something else happening in this same spot, a memory of being in this much pain before, or the crucial decision in the past that led the protagonist to this outcome.

In fiction or nonfiction, a common tip is to write the flashback as a complete scene. In screenplays, flashbacks are often truly just flashes—quick, visual representations of what the character feels or remembers. Be sure to orient the audience in time and place by showing when and where the flashback takes place and which people matter in it.

Shifts in verb tense usually signal the beginning and end of a flashback. If the rest of the piece is in past tense, then use past-perfect for the flashback. (If the flashback is long, then past-perfect may become cumbersome. Create a consistent rule for yourself, such as: the first paragraph and the last paragraph of the flashback are in past perfect, while everything in between is in past.) If the rest of the piece is in the present tense, then write in simple past tense for the flashback.

With these tips in mind, your flashbacks will light up the sky to guide the audience through your story.