Years ago, when I was in my 20s, I heard an interview with the composer Aaron Copland. The interviewer asked why it had been more than a decade since Copland’s last completed composition. I thought the question was insensitive, but Copland’s answer frightened me: “Songs stopped coming to me,” he said.

I wasn’t a published writer at the time, but I was a lifelong writer of stories and poems. These were a private exploration of an interior landscape. My earliest memories include the stories that came to me when I was a small child. The thought that these might stop (“as if someone turned off a faucet,” Copland also said) is as terrifying to me today as it was all those years back.

I write because stories come to me. I love language, I love playing with words, and rewriting and reworking, trying to polish, trying to explore new narrative strategies, but I write stories, not words. At night, I often tell myself a bedtime story—not a good activity for a chronic insomniac, by the way: the emotions become too intense for rest. When I was a child and an adolescent, the bedtime stories were versions of my wishes. They usually depicted safe and magical places. I was never a hero in my adventures; I was someone escaping into safety.

As a young adult, I imagined myself as a published writer. For many years, the story I told myself was of becoming a writer. Over a period of eight years, that imagined scenario slowly made me strong enough to try to write for publication. After V.I. Warshawski came into my life, my private narratives changed again.

Story lines are suggested by many things—people I meet, books I’m reading, news stories I’m following—but the stories themselves come from a place whose location I don’t really know. I imagine it as an aquifer, some inky underground reservoir that feeds writers and painters and musicians and anyone else doing creative work.

There have been times when, in Copland’s phrase, the faucet’s been turned off; my entry to the aquifer has been shut down. No stories arrive and I panic, wondering if this is it, the last story I’ll ever get, as Copland found himself with the last song. If that ever happens permanently, I don’t know what I’ll do.

So far, each time, the spigot has miraculously been turned on again; the stories come back, I start writing once more. Each time it happens, though, I return to work with an awareness that I’ve been given a gift that can vanish like a lake in a drought.

Sara Paretsky is the author of 18 books. In January, Putnam will publish Breakdown.