Next month sees the publication of Philip Pullman’s La Belle Sauvage, the long-awaited first volume of The Book of Dust, an epic fantasy trilogy intended to stand alongside his bestselling series, His Dark Materials.

Pullman devotees have waited 17 years for him to return to the magical world of Northern Lights, The Subtle Knife and The Amber Spyglass, which have together sold more than 17.5m copies and been translated into 40 languages.

The new series is not a sequel or a prequel, but an “equel”, Pullman told the Today programme on BBC Radio 4 when it was first announced. But apart from revealing that his brave and outspoken heroine Lyra Belacqua will once more be at the centre of the story, he has been, in his own words, “very parsimonious with information” about The Book of Dust.

In a couple of weeks, Observer literary editor Lisa O’Kelly will visit the master storyteller in Oxford to interview him on behalf of readers. This is your chance to put questions to the author who has shaped the imagination of a generation. Why has he finally returned to Lyra’s world? What is the significance of “Dust”, the mysterious substance at the centre of the original books and presumably at the heart of the new series? What parallels should we draw between the “despotic and totalitarian organisation, which wants to stifle speculation and inquiry” that Pullman has revealed lies at the heart of the new book and current political events?

While you’re at it, you might also want to ask this staunch Remainer how he feels about the progress of Brexit. Or the state of the nation’s schools, another subject close to his heart – as is organised religion. “My books are about killing God,” he has said. Things could get pretty lively.

How you can put your questions to Philip Pullman

Post your questions by 10am on Tuesday 3 October, either below the line here, or tweet them to @ObsNewReview or by email to review@observer.co.uk.