Both of these examples are collections of folk tales. Arabian Nights in particular has no authoritative original at all, and there are many variations of the co

Both of these examples are collections of folk tales. Arabian Nights in particular has no authoritative original at all, and there are many variations of the collection in many languages, many of which which are still available today from a variety of publishers. The Brothers Grimm similarly collected and adapted folk tales (and bowdlerized _their own work_ in subsequent editions), but reprints of most of these editions are still available, and versions of tales or collections that were not written by the Grimms are not published under their name. By contrast Dahl stories are original IP with an authoritative source who is now dead and can't revise his own work.