More than 35 years after the legendary crime writer's death, Agatha Christie's estate has authorized the first new Christie novel since 1976's Sleeping Murder

This isn't a case of an unpublished manuscript, like the ones J.D. Salinger reportedly left behind. Christie, who authored 66 detective novels and has sold about four billion books, more than exhausted her literary inspiration muse during her lifetime. This is a continuation novel, to be authored by the popular British crime novelist Sophie Hannah. And it will feature recurring Christie character Hercule Poirot, the fictional Belgian detective who first appeared in her 1920 debut novel, The Mysterious Affair at Styles.

Hannah, according to a press release from publisher HarperCollins, is delighted and humbled by the project:

Hannah, a leading writer of psychological crime fiction who is published in 24 countries, says, “It is almost impossible to put into words how honored I am to have been entrusted with this amazing project—in fact, I still can't quite believe that this is really happening! I hope to create a puzzle that will confound and frustrate the incomparable Hercule Poirot for at least a good few chapters.”

Which begs the question, how does one get commissioned to write a "new" Agatha Christie novel? Unsurprisingly, you have to be a devout disciple of Christie. Being an internationally published crime novelist doesn't hurt, either.

Plus, a bit of luck.

"It was pure serendipity that led to Sophie Hannah being commissioned to write this book," Christie's grandson, Mathew Prichard, explains in the press release. "Her agent happened to approach HarperCollins in exactly the same week that my colleagues and I started discussing a new Christie book. Her idea for a plot line was so compelling and her passion for my grandmother’s work so strong, that we felt that the time was right for a new Christie to be written."

Oh, and a tireless literary drive—one of Christie's most intense qualities. Hannah, fittingly, is also working on a new book of her own, to be titled The Telling Error. That book will be out in April; the Christie novel will follow in September, 2014.