Susanna Clarke's next two books will be published by Bloomsbury globally, 16 years after her bestselling debut Jonathan Strange & Mr Norrell.

Piranesi, about the secrets of a “watery labyrinth”, will be published globally by Bloomsbury in September 2020 along with an “ambitious and ground-breaking marketing and publicity campaign”. A second novel will follow.

Jonny Geller at Curtis Brown sold world English rights for the two titles jointly to Bloomsbury publishing editor-in-chief Alexandra Pringle and Bloomsbury USA editorial director for fiction Liese Mayer.

“There are a few moments in an agent’s life when something so unexpected and so wonderful pops up in your inbox, you can’t quite believe it,” Geller said. “Susanna hinted she may be writing again after such a long hiatus, but I never really believed a fully imagined world, a perfectly constructed novel, would just be sitting there. I’m so excited for her legions of fans worldwide to read Piranesi next year and am delighted Bloomsbury UK and US will be weaving their magic once again for the author of Jonathan Strange.”

“Piranesi has always lived in the House,” the synopsis reads. “It has hundreds if not thousands of rooms and corridors, imprisoning an ocean. A watery labyrinth. Once in a while he sees his friend, The Other, who needs Piranesi for his scientific research into A Great and Secret Knowledge. Piranesi records his findings in his journal. Then messages begin to appear; all is not what it seems. A terrible truth unravels as evidence emerges of another person and perhaps even another world outside the House’s walls.”

Pringle said: “Once in a lifetime do you get to publish a book that becomes encoded in the very DNA of who you are as a publisher. For me and for Bloomsbury, that book was Jonathan Strange & Mr Norrell: a book that appeared from the ether like an apparition. I had thought it couldn’t be equalled; but when I followed Piranesi into his watery Halls, I discovered Susanna’s wit, strangeness and sorrow made new and beautiful in ways I could not have imagined. It will be an honour to open the doors to the House, and show its beauty to the world.”

Mayer said: “More than a decade ago, Jonathan Strange & Mr Norrell took the world by storm. It is a profound privilege to publish Susanna’s new novel, Piranesi, and we couldn’t be more excited. Piranesi is an intricate, fascinating puzzle, with a moving mystery at its core.”

She added: “When I stepped back and looked at the world that puzzle had formed, I found a universe – complete and contained and dazzling to behold.”

Clarke's previous novel Jonathan Strange & Mr Norrell was published by Bloomsbury in 2004. Longlisted for the Man Booker Prize and winner of the British Book Awards Newcomer of the Year, the Hugo Award the World Fantasy Award and the Locus Award for Best First Novel, it spent 11 weeks on the New York Times bestsellers list. It has sold 412,622 copies total for £3.2m, with the 2005 paperback edition of Jonathan Strange and Mr Norrell selling 230,740 copies, according to Nielsen BookScan. Translated into 34 languages, it was also adapted into a major primetime series by the BBC and BBC America starring Bertie Carvel and Eddie Marsan. As well as her bestselling debut, she wrote a collection of short stories, The Ladies of Grace Adieu (Bloomsbury, 2006).

Clarke was born in Nottingham and now lives in Cambridge. In 1990 she left London to teach English in Turin and Bilbao for two years before returning to England to work at Simon and Schuster as a cookery editor.