This is one of the few Dahl books that I didn't read a child. As with all Dahl books, it has some really nasty adults in it. Matilda is clever. Very, very clever. She also has pretty useless parents, who at best neglect her and are too stupid themselves to realise how brainy their daughter is.
Matilda attends the local school, and is taught by the very lovely Miss Honey, who in turn works for the awful headmistress, Miss Trunchbull. Miss Honey can see how clever Matilda is and tries to help her. Meanwhile Miss Trunchbull is preparing increasingly abusive punishments for any minor misdemeanours her charges may undertake.
This is a brilliant book. Miss Trunchbull is a truly horrible character, very dark and very macabre. She of course gets what's coming to her, but not before Matilda and Miss Honey have gone through some mild peril. It's funny and icky and exciting. All the things children (and some grown-ups, that is to say, me) love.