I only know A. A. Milne as the author of the Winnie-the-Pooh books, so it must have been a bit of a change of direction for him too.

XD Pooh is also what I knew him from--apparently he wrote this one for his father, who liked mysteries. I wasn't sure if I'd mentioned it before, because when I read "Witching hill" after you recommended it, the vibe between Gilly and Uvo reminded me a little bit of this book's main characters! I think this gives more strength to the rec, right? :D