Harriet is an 11-year-old snub-nosed gamin with an elephant child curiosity and, let's face it, a noticing eye that runs to nastiness.
She lives in the city with her parents, generally not around, Miss Golly the nursemaid she had almost outgrown, and she spends all her time annotating what she sees since she wants to be a writer and a ""spy and know everything."" In any case, she often knows too much and this Junior Miss Pinkerton is seen inserting herself everywhere- even in dumbwaiters. After Miss Golly leaves to get married, things go very poorly; Harriet's journal is found by her classmates who pillory her when they read what she has said about them. Her thoughts get meaner and meaner. She does no work in school. There's a (nicely handled) visit to a psychiatrist and then a letter from Miss Golly who gives her some pragmatic advice—"sometimes you have to lie" or apologize...
Whether some adults will find this morally unregenerative, still it's a thoroughly realistic story with lost of very funny scenes and commentaries, and it features one of the hardest to handle, easiest to like heroines in a long time. Illustrations by the author not seen.