Standard advice for fiction writers usually includes “Start in the middle.” Good advice, for the most part, but how do you work in all the important stuff that’s happened before the story starts, the backstory?

Backstory often gets a bad rap. It’s associated with info dumps, superfluous prologues, and abrupt jumps back in time.

But backstory is crucial, not just the backstory for the situation but the backstory of each character. (Come to think of it, these overlap so heavily that they might almost be the same thing.) Lately I’ve become a huge fan of Sally Wainwright, the British screenwriter who’s largely responsible for such series as Last Tango in Halifax, Scott and Bailey, and Happy Valley. She’s created some of the most three-dimensional, complex, recognizable characters I’ve ever seen on small screen or large — or in novels, for that matter.

A big reason is that Wainwright’s characters have pasts. Where they’ve come from helps shape who they are, yes, but their histories also help drive the plot. Unexpected events in the present trigger memories of the past; those memories affect how they respond to the events. Their friends and co-workers see them in a different, perhaps surprising light.

Most of us have memories that we would rather keep in the closet, safe from prying eyes — including our own. When events force them into the open, we have plot.

In “Notes and More Notes” I wrote that for me “writing is a journey of discovery. If I know in advance what I’m going to discover, why make the trip? I’m just a sightseer gazing through the windows of a tour bus.”

In Wolfie, the novel in progress, much of what I’m discovering is about backstory. I already knew that protagonist Shannon fled her violently alcoholic family as a teenager. Now, in the late stages (I hope) of draft #2, I, along with Shannon, am learning what happened after she left, thanks to an unexpected phone call from Shannon’s estranged younger sister. As a result, draft #3 is going to have a plot thread that’s completely absent from the first three-quarters of draft #2.

This might drive a careful planner nuts. Planners often want to know a character’s history cold before they get down to writing. What happens when unruly backstory starts to erupt out of the carefully planned tale?  Maybe it doesn’t happen. Maybe serendipity doesn’t bother to knock where it knows it won’t be welcome.

If I were on deadline, if I had to deliver a final draft to a publisher by, say, the end of April, I probably wouldn’t hear the knocking. Or maybe I’d scream so loud at the intrusion that serendipity would cower in the shadows and hesitate to come back. This is part of why I’ve never aspired to write for a living, though I wouldn’t turn down fame, fortune, and/or more time if they came knocking.

But I’m not on deadline, and for the moment I’m grateful. I knew almost at once that this particular plot thread was meant to be in the novel. It fits. It’s been exerting a sort of gravitational pull on Shannon all her adult life, but for a long time Shannon wasn’t dealing with it so I didn’t have a clue. Other events flushed it out of hiding.

Backstory happens if you let it happen. Your characters will help you with this. They’ll say or do something that makes you wonder: Where did that come from? And in a few moments you have the kernel of an earlier incident that will become part of the character’s backstory.

These incidents may loom large in the character’s memory long after everyone else in the vicinity has forgotten them. When I was 13, I was told by another kid in my church choir that I always sang off-key. No one else ever told me that, and I didn’t even like this kid, but I was so afraid she was right that I stopped singing for almost 20 years. Most of us have had experiences like that. So have our characters. In our heads we’re often arguing with people who passed out of our lives years or even decades earlier. Listen.