Unfortunately, I think that the [i:9e5d079002]Lancre[/i:9e5d079002] witch books have probably reached their limits - there are only so many threats to Lancre to be foiled by Granny Weatherwax, and she can't be broomsticking all over the place at her age (but don't tell her that!) - Tiffany will, I am sure, always remain loyal to the Chalk, so it looks probable that Nanny Ogg, Magrat, Verence, Agnes and of course Greebo may fade into the background - although you never know - Ankh-Morpork is such fertile soil (and that's just the river!) for new stories, what are the possibilities for the witches to meet the Watch?