If you have ever wondered whether the dwarf women of Middle-earth could grow beards, wonder no more. Superfans of JRR Tolkien are to learn more about the rich world he invented for The Lord of the Rings and other novels when a collection of unpublished essays is released next year.

The Nature of Middle-earth will feature essays by the British author that have remained unknown for more than 40 years. They answer questions, long argued over by Tolkien scholars and fans, about hirsute dwarf characters, the geography of Gondor and the nature of the elves’ immortality. They have been brought to light thanks to the patient editing of Carl Hostetter, a Nasa software engineer and one of the world’s foremost Tolkien experts, who was given access to the manuscripts by the author’s son.

Chris Smith, deputy publishing director at Harper Collins, which is the publisher for Tolkien’s estate, said: “This new collection is a veritable treasure trove, offering readers a chance to peer over Professor Tolkien’s shoulder at the very moment of discovery: and on every page, Middle-earth is once again brought to extraordinary life.” After Tolkien’s death in 1973, aged 81, his son Christopher spent four decades preparing and releasing books from his father’s unpublished work, including The Silmarillion, The Children of Húrin and the 12-volume History of Middle-earth. By the time of his death in January this year, aged 95, he had not started on the Nature of Middle-earth, and gave his blessing to Mr Hostetter to continue the work.

“On every page, Middle-earth is once again brought to extraordinary life.”

David Brawn, publisher of estates at HarperCollins, said: “Such did J.R.R. Tolkien care about his sub-created world that it must attain the highest sense of reality and credibility, making sense on the most profound and all-encompassing level, and this endeavor would occupy him for more than two decades.”

The Tolkien estate continues to offer a rich seam of fresh material and adaptations. In November 2017, Amazon won a bidding war against Netflix for the rights to serialize a Lord of the Rings adaptation on its streaming platform, paying $250 million for a deal with the Tolkien estate, HarperCollins and Warner Bros. Amazon has promised “a new epic journey in Middle-earth”.