God help me, but I can't manage to watch this film. I've tried, but I can't get further than 5 or 6 minutes into it. I find the child endangerment theme too disturbing. Much too disturbing. I don't know if this is something that would ease as the film continues, but I can't get past that poor little girl....
Ah, well, perhaps it's best to just leave it for now.
The CriterionCollection blog has a review of M. As much as I like Peter Lorre and Fritz Lang I still haven't watched this film.