I got this news item from multiple sources on Twitter. I've not read the books or watched their associated movies, but I figure I've readers who have, so.
Titus Awakes was written by Maeve Gilmore shortly after her husband's death from Parkinson's Disease in 1968.
She decided to write the book, which runs to 210 pages, after he left her a page and a half of fragmented notes about how he might have continued the story.
The Gormenghast series, which is often wrongly called a trilogy but was in fact intended to be a longer series, followed the path of Titus Groan from his birth, as heir to a crumbling medieval castle, to his encounters in a modern world of skyscrapers and inventions.
Peake started writing the first, Titus Groan, in 1940. The second, Gormenghast, was published in 1950 while the third, Titus Alone, was published in 1959, three years after he stared to suffer from Parkinson's.
But his son Sebastian Peake, 69, believes he intended to write a whole series of books charting Titus's life from cradle to grave.
He said: "Following his death, my mother decided to see whether she could continue the Titus story, that my father was not able to finish before he was totally incapacitated."
In July 1960 he had written her an introduction for the new novel, and the briefest of outlines of how it might continue, with him visiting places such as "mountains, beaches, caves".
It starts with Titus leaving Castle Gormenghast. Peake wrote: "With every pace he drew away from Gormenghast mountain, and from everything that belonged to his home. That night, as Titus lay asleep in the tall barn, a nightmare held him."
His wife, who died in 1983, continued the story: "Titus awoke from his haunted sleep. His nose was frozen. He could not feel the extremities of his being. His toes were immobilised, fingers he dared not uncurl, for fear of them snapping off as brittle as a piece of homemade toffee."
The existence of her manuscript, handwritten in brown ink in four exercise books, remained unknown until Sebastian Peake's daughter Christian discovered them in the attic of her south London home.