Writers are often told to do this, don’t do that. Then someone comes along and tells them the opposite. One thing they are often told not to use are flashbacks. Author and publisher Jeff Gerke writes in The First 50 Pages:
But if your whole purpose for doing a flashback is to reveal backstory, it’s de facto telling. You’re still stopping the story (the main, present-day story) to explain something, and it’s probably something the reader doesn’t care about…Avoid flashbacks if you can.
I would normally agree. Flashbacks are often poorly used. In recent years, however, film and television have showed us how to seamlessly use flashbacks in storytelling. We owe much of that to Lost.
Flashbacks revealing the pasts of characters were integral to Lost‘s writing. The premise behind the technique was that we rarely ever start with a character at birth and see their whole life. We nearly always start in situ somewhere in their timeline.
Ever read a scene that is obviously trying to show something about a character that comes across forced? There’s often enough going on in the current story that the backstory will get the shaft or feel out of place. Flashbacks can solve this if — and pay attention to this if — they are fluid and seamless. The reader clearly knows, or soon will know, the time has changed. It must feel like the story hasn’t stopped or slowed. Your reader shouldn’t be jarred. Visually, on television, this is all a bit easier. Do you need to preface a flashback with a notation such as “6 years ago…” If you have to do that, the scene is probably not seamless enough or you’re not showing enough in your story. If you do that well, then trust your readers. Don’t be like films that subtitle “Washington, D.C.” over a shot of the Mall and its monuments.
So like many techniques, flashbacks can be done right or wrong. See how television has done it right so you won’t do it wrong.