Suzanne Collins’ highly anticipated prequel to the Hunger Games books, The Ballad of Songbirds and Snakes, was published today, and the author talked about the origins of the novel in an interview with one of her editors, David Levithan, shared by the publisher, Scholastic.

Asked what made her return to Panem for her latest book, Collins said, “I have two worlds, the Underland (the world of The Underland Chronicles) and Panem (the world of The Hunger Games). I use both of them to explore elements of just war theory. When I find a related topic that I want to examine, then I look for the place it best fits.”

Collins said she wanted to tell the story of Lucy Gray, a character mentioned in passing in her previous books.

“In the first chapter of The Hunger Games, I make reference to a fourth District 12 victor,” Collins said. “Katniss doesn’t seem to know anything about the person worth mentioning. While her story isn’t well-known, Lucy Gray lives on in a significant way through her music, helping to bring down [Coriolanus] Snow in the trilogy.”

Collins also discussed her decision to set the novel 64 years prior to the events of The Hunger Games.

“I thought a lot about the period after the Civil War here in the United States and also the post–World War II era in Europe,” she said. “People trying to rebuild, to live their daily lives in the midst of the rubble. The challenges of food shortages, damaged infrastructure, confusion over how to proceed in peacetime. The relief that the war has ended coupled with the bitterness toward the wartime enemy. The need to place blame.”

The Ballad of Songbirds and Snakes seems certain to be a blockbuster like its predecessors. As of this morning, the novel was ranked No. 1 among all books at Amazon.

Michael Schaub is a Texas-based journalist and regular contributor to NPR.