Sort of sequels

A few years ago Great Ormond Street Hospital (to whom J.M. Barrie gifted the rights to Peter Pan) commissioned children's author Geraldine McCaughrean to write the official sequel, Peter Pan in Scarlet. There have been several unofficial sequels, including Wendy by Karen Wallace, but most haven't been available in the UK due to copyright laws. I have a copy (hardback, I really wanted to read it) but I don't think McCaughrean's measures upto Barrie's original (properly called Peter and Wendy) which I have as both the novel and the playscript he wrote first. Barrie's writing is lyrical and at times, haunting. Lines such as "to die would be an awfully big adventure" are actually quite scary when you think about it, he draws on older forms "rosy fingered dawn" is a line from The Iliad. McCaughrean is a good writer, but too much time and water has flowed since Barrie wrote his enduring story of the boy who never wanted to grow up. One its own, Peter Pan in Scarlet is a good book, I just wish it wasn't picking up from another writer's book, that rarely works out well.
Another writer picking up the threads of an older novel is William Horwood, who has written a series of books following on from Kenneth Grahame's much loved Wind in the Willows. So far there's The Willows in Winter, The Willows and Beyond and Toad Triumphant. I've only read the first one of those, and that was some time ago. I love Grahame's lovely little book, re-reading it as an adult has meant I've picked up on several things I missed as a child reader. The chapter "Piper at the Gates of Dawn" for example, seems to belong to another narrative altogether, but is beautiful and moving.
Frank Beddor's The Looking Glass Wars and Seeing Redd reimagine Lewis Carroll's Alice in Wonderland and Through the Looking Glass, as an alternative world, where Alice is the daughter of the White King and Queen, fighting a war against her aunt, the Red Queen. Alice is sent through the Looking Glass to Victorian England, where she is taken in by the Liddells, and raised as their odd, adoptive daughter, who tells the story of her real home to the kindly Rev Dodgson (aka Carroll). Not a sequel as such, but part of a growing trend of 're-imaginings'.
Also in that category are Gregory Maguire's Wicked books, Wicked, Son of a Witch and A Lion Among Men. These re-imagine Frank L. Baum's Oz books from the perspective of Elphaba, the Wicked Witch of the West, and then her descendents and other people whose lives intersected with hers.
This seems to be part of a wider tradition of re-telling, something that the Brothers Grimm were part of when they travelled round Europe collecting folklore and fairy tales. Angela Carter retold some of those tales in the 20th Century, retellings of retellings if you like.
There are many other unofficial sequels, but it seems quite prevalent in children's literature especially, which strikes me as something of a shame, it detracts a little from the glory of the orginals. It's up to time really, to see if these last as long as those stories they're based on.